diff --git a/compass/landice/tests/ismip7_forcing/atmosphere/__init__.py b/compass/landice/tests/ismip7_forcing/atmosphere/__init__.py
index 7e577b2026..6c49cb98ad 100644
--- a/compass/landice/tests/ismip7_forcing/atmosphere/__init__.py
+++ b/compass/landice/tests/ismip7_forcing/atmosphere/__init__.py
@@ -1,3 +1,6 @@
+from compass.landice.tests.ismip7_forcing.atmosphere.build_mapping_file import (  # noqa: E501
+    BuildMappingFile,
+)
 from compass.landice.tests.ismip7_forcing.atmosphere.process_runoff import (
     ProcessRunoff,
 )
@@ -40,6 +43,7 @@ def __init__(self, test_group):
         subdir = name
         super().__init__(test_group=test_group, name=name, subdir=subdir)
 
+        self.add_step(BuildMappingFile(test_case=self))
         self.add_step(ProcessSmb(test_case=self))
         self.add_step(ProcessTemperature(test_case=self))
         self.add_step(ProcessSmbGradient(test_case=self))
diff --git a/compass/landice/tests/ismip7_forcing/atmosphere/build_mapping_file.py b/compass/landice/tests/ismip7_forcing/atmosphere/build_mapping_file.py
new file mode 100644
index 0000000000..f990d58a6a
--- /dev/null
+++ b/compass/landice/tests/ismip7_forcing/atmosphere/build_mapping_file.py
@@ -0,0 +1,147 @@
+import os
+import shutil
+
+from compass.landice.ismip7.ice_sheet_params import get_params
+from compass.landice.ismip7.mapping import build_mapping_file
+from compass.step import Step
+
+
+class BuildMappingFile(Step):
+    """
+    A step for building the ESMF mapping file (regridding weights) from
+    the ISMIP7 atmosphere grid to the MALI mesh. This step runs
+    ESMF_RegridWeightGen with the full esmf_ntasks allocation, so it can
+    be run on a separate node allocation from the processing steps (which
+    run on a single node).
+
+    The mapping file can be reused across scenarios, since it depends only on
+    the ice sheet, mesh name, and remapping method. If mapping_files_path is
+    provided in the config, this step will symlink any existing weight file
+    from that directory and skip the build.
+    """
+
+    def __init__(self, test_case):
+        """
+        Create the step
+
+        Parameters
+        ----------
+        test_case : compass.landice.tests.ismip7_forcing.atmosphere.Atmosphere
+            The test case this step belongs to
+        """
+        super().__init__(test_case=test_case, name="build_mapping_file")
+
+    def setup(self):
+        """
+        Set up this step of the test case
+        """
+        config = self.config
+        section = config["ismip7"]
+        base_path_mali = section.get("base_path_mali")
+        mali_mesh_file = section.get("mali_mesh_file")
+
+        self.add_input_file(filename=mali_mesh_file,
+                            target=os.path.join(base_path_mali,
+                                                mali_mesh_file))
+
+        # Request the full esmf_ntasks allocation for this step
+        self.ntasks = section.getint("esmf_ntasks")
+        self.min_tasks = self.ntasks
+
+    def run(self):
+        """
+        Run this step of the test case
+        """
+        logger = self.logger
+        config = self.config
+        params = get_params(config)
+
+        section = config["ismip7"]
+        base_path_ismip7 = section.get("base_path_ismip7")
+        mali_mesh_name = section.get("mali_mesh_name")
+        mali_mesh_file = section.get("mali_mesh_file")
+        ice_sheet = section.get("ice_sheet")
+        output_base_path = section.get("output_base_path")
+
+        # Check if user provided a path to reuse existing weight files
+        mapping_files_path = section.get("mapping_files_path")
+
+        section = config["ismip7_atmosphere"]
+        method_remap = section.get("method_remap")
+
+        # Construct the canonical mapping file name
+        mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
+                        f"{mali_mesh_name}_{method_remap}.nc")
+
+        # If mapping_files_path is provided, symlink any existing file
+        if mapping_files_path != "NotAvailable":
+            source_file = os.path.join(mapping_files_path, mapping_file)
+            if os.path.exists(source_file):
+                logger.info(f"Symlinking existing mapping file from "
+                            f"{mapping_files_path}")
+                if os.path.exists(mapping_file):
+                    os.remove(mapping_file)
+                os.symlink(source_file, mapping_file)
+
+        # Use any atmosphere file as the grid template for building the
+        # mapping file. We'll use the first year's acabf (SMB) file.
+        ismip7_section = config["ismip7"]
+        base_path_ismip7 = ismip7_section.get("base_path_ismip7")
+        mali_mesh_name = ismip7_section.get("mali_mesh_name")
+        mali_mesh_file = ismip7_section.get("mali_mesh_file")
+        ice_sheet = ismip7_section.get("ice_sheet")
+        output_base_path = ismip7_section.get("output_base_path")
+        mapping_files_path = ismip7_section.get("mapping_files_path")
+
+        atmosphere_section = config["ismip7_atmosphere"]
+        method_remap = atmosphere_section.get("method_remap")
+
+        prefix = params["prefix"]
+        resolution = params["atm_resolution"]
+        version = params["atm_version"]
+
+        model = (ismip7_section.get("model")
+                 if params["atm_model"] is None
+                 else params["atm_model"])
+
+        scenario = ismip7_section.get("scenario")
+
+        input_path = os.path.join(base_path_ismip7, "acabf", version)
+        # Use a simple pattern that will match the first available file
+        file_pattern = (f"acabf_{prefix}_{model}_{scenario}_"
+                        f"SDBN1-{resolution}_{version}_*.nc")
+        ismip7_grid_file = os.path.join(input_path, file_pattern)
+
+        import glob
+        grid_files = sorted(glob.glob(ismip7_grid_file))
+        if not grid_files:
+            raise FileNotFoundError(
+                f"No atmosphere grid file found matching pattern:\n"
+                f"  {ismip7_grid_file}")
+        ismip7_grid_file = grid_files[0]
+        logger.info(f"Using grid template: "
+                    f"{os.path.basename(ismip7_grid_file)}")
+
+        # Build the mapping file (build_mapping_file will skip if it already
+        # exists, e.g., from the symlink above or a previous failed run)
+        build_mapping_file(config, logger, ismip7_grid_file, mapping_file,
+                           mali_mesh_file=mali_mesh_file,
+                           method_remap=method_remap)
+
+        # Copy the mapping file to output_base_path/mapping_files/ for reuse
+        # in future runs
+        mapping_files_dir = os.path.join(output_base_path, "mapping_files")
+        if not os.path.exists(mapping_files_dir):
+            os.makedirs(mapping_files_dir)
+
+        dst = os.path.join(mapping_files_dir, mapping_file)
+        # Only copy if it's a real file (not a symlink we just created)
+        if not os.path.islink(mapping_file):
+            logger.info(f"Copying mapping file to {mapping_files_dir} "
+                        f"for reuse")
+            shutil.copy(mapping_file, dst)
+        else:
+            logger.info(f"Mapping file is a symlink; not copying to "
+                        f"{mapping_files_dir}")
+
+        logger.info("Done building atmosphere mapping file.")
diff --git a/compass/landice/tests/ismip7_forcing/atmosphere/process_runoff.py b/compass/landice/tests/ismip7_forcing/atmosphere/process_runoff.py
index 8125abe250..39282d1955 100644
--- a/compass/landice/tests/ismip7_forcing/atmosphere/process_runoff.py
+++ b/compass/landice/tests/ismip7_forcing/atmosphere/process_runoff.py
@@ -7,7 +7,6 @@
 from mpas_tools.logging import check_call
 
 from compass.landice.ismip7.ice_sheet_params import get_params
-from compass.landice.ismip7.mapping import build_mapping_file
 from compass.landice.ismip7.remap import extrapolate_source
 from compass.step import Step
 
@@ -38,11 +37,22 @@ def setup(self):
         section = config["ismip7"]
         base_path_mali = section.get("base_path_mali")
         mali_mesh_file = section.get("mali_mesh_file")
+        mali_mesh_name = section.get("mali_mesh_name")
+        ice_sheet = section.get("ice_sheet")
+
+        section_atm = config["ismip7_atmosphere"]
+        method_remap = section_atm.get("method_remap")
 
         self.add_input_file(filename=mali_mesh_file,
                             target=os.path.join(base_path_mali,
                                                 mali_mesh_file))
 
+        # Add input file for the mapping file from build_mapping_file step
+        mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
+                        f"{mali_mesh_name}_{method_remap}.nc")
+        self.add_input_file(filename=mapping_file,
+                            target=f"../build_mapping_file/{mapping_file}")
+
     def run(self):
         """
         Run this step of the test case
@@ -54,7 +64,6 @@ def run(self):
         section = config["ismip7"]
         base_path_ismip7 = section.get("base_path_ismip7")
         mali_mesh_name = section.get("mali_mesh_name")
-        mali_mesh_file = section.get("mali_mesh_file")
         model = section.get("model")
         scenario = section.get("scenario")
         output_base_path = section.get("output_base_path")
@@ -103,17 +112,11 @@ def run(self):
         logger.info(f"Found {len(input_files)} runoff files for years "
                     f"{start_year}-{end_year}")
 
-        # Build mapping file (reuse if already created by other atm steps)
+        # Construct the mapping file name (symlinked from
+        # build_mapping_file step)
         mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
                         f"{mali_mesh_name}_{method_remap}.nc")
 
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file...")
-            build_mapping_file(config, logger,
-                               input_files[0], mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
-
         # Remap each year file
         remapped_files = []
         for input_file in input_files:
diff --git a/compass/landice/tests/ismip7_forcing/atmosphere/process_smb.py b/compass/landice/tests/ismip7_forcing/atmosphere/process_smb.py
index 9701265638..0b2aed2a54 100644
--- a/compass/landice/tests/ismip7_forcing/atmosphere/process_smb.py
+++ b/compass/landice/tests/ismip7_forcing/atmosphere/process_smb.py
@@ -7,7 +7,6 @@
 from mpas_tools.logging import check_call
 
 from compass.landice.ismip7.ice_sheet_params import get_params
-from compass.landice.ismip7.mapping import build_mapping_file
 from compass.landice.ismip7.remap import extrapolate_source
 from compass.step import Step
 
@@ -38,11 +37,22 @@ def setup(self):
         section = config["ismip7"]
         base_path_mali = section.get("base_path_mali")
         mali_mesh_file = section.get("mali_mesh_file")
+        mali_mesh_name = section.get("mali_mesh_name")
+        ice_sheet = section.get("ice_sheet")
+
+        section_atm = config["ismip7_atmosphere"]
+        method_remap = section_atm.get("method_remap")
 
         self.add_input_file(filename=mali_mesh_file,
                             target=os.path.join(base_path_mali,
                                                 mali_mesh_file))
 
+        # Add input file for the mapping file from build_mapping_file step
+        mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
+                        f"{mali_mesh_name}_{method_remap}.nc")
+        self.add_input_file(filename=mapping_file,
+                            target=f"../build_mapping_file/{mapping_file}")
+
     def run(self):
         """
         Run this step of the test case
@@ -54,7 +64,6 @@ def run(self):
         section = config["ismip7"]
         base_path_ismip7 = section.get("base_path_ismip7")
         mali_mesh_name = section.get("mali_mesh_name")
-        mali_mesh_file = section.get("mali_mesh_file")
         model = section.get("model")
         scenario = section.get("scenario")
         output_base_path = section.get("output_base_path")
@@ -102,18 +111,12 @@ def run(self):
         logger.info(f"Found {len(input_files)} SMB files for years "
                     f"{start_year}-{end_year}")
 
-        # Build mapping file using the first input file as the grid template
+        # Construct the mapping file name (symlinked from
+        # build_mapping_file step)
         ice_sheet = config.get("ismip7", "ice_sheet")
         mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
                         f"{mali_mesh_name}_{method_remap}.nc")
 
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file...")
-            build_mapping_file(config, logger,
-                               input_files[0], mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
-
         # Remap each year file
         remapped_files = []
         for input_file in input_files:
diff --git a/compass/landice/tests/ismip7_forcing/atmosphere/process_smb_gradient.py b/compass/landice/tests/ismip7_forcing/atmosphere/process_smb_gradient.py
index e35755e9b6..08cc2c971a 100644
--- a/compass/landice/tests/ismip7_forcing/atmosphere/process_smb_gradient.py
+++ b/compass/landice/tests/ismip7_forcing/atmosphere/process_smb_gradient.py
@@ -7,7 +7,6 @@
 from mpas_tools.logging import check_call
 
 from compass.landice.ismip7.ice_sheet_params import get_params
-from compass.landice.ismip7.mapping import build_mapping_file
 from compass.landice.ismip7.remap import extrapolate_source
 from compass.step import Step
 
@@ -39,11 +38,22 @@ def setup(self):
         section = config["ismip7"]
         base_path_mali = section.get("base_path_mali")
         mali_mesh_file = section.get("mali_mesh_file")
+        mali_mesh_name = section.get("mali_mesh_name")
+        ice_sheet = section.get("ice_sheet")
+
+        section_atm = config["ismip7_atmosphere"]
+        method_remap = section_atm.get("method_remap")
 
         self.add_input_file(filename=mali_mesh_file,
                             target=os.path.join(base_path_mali,
                                                 mali_mesh_file))
 
+        # Add input file for the mapping file from build_mapping_file step
+        mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
+                        f"{mali_mesh_name}_{method_remap}.nc")
+        self.add_input_file(filename=mapping_file,
+                            target=f"../build_mapping_file/{mapping_file}")
+
     def run(self):
         """
         Run this step of the test case
@@ -55,7 +65,6 @@ def run(self):
         section = config["ismip7"]
         base_path_ismip7 = section.get("base_path_ismip7")
         mali_mesh_name = section.get("mali_mesh_name")
-        mali_mesh_file = section.get("mali_mesh_file")
         model = section.get("model")
         scenario = section.get("scenario")
         output_base_path = section.get("output_base_path")
@@ -103,18 +112,12 @@ def run(self):
         logger.info(f"Found {len(input_files)} SMB gradient files for years "
                     f"{start_year}-{end_year}")
 
-        # Build mapping file (reuse if already created by process_smb)
+        # Construct the mapping file name (symlinked from
+        # build_mapping_file step)
         ice_sheet = config.get("ismip7", "ice_sheet")
         mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
                         f"{mali_mesh_name}_{method_remap}.nc")
 
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file...")
-            build_mapping_file(config, logger,
-                               input_files[0], mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
-
         # Remap each year file
         remapped_files = []
         for input_file in input_files:
diff --git a/compass/landice/tests/ismip7_forcing/atmosphere/process_temperature.py b/compass/landice/tests/ismip7_forcing/atmosphere/process_temperature.py
index 56b13403be..441f07d518 100644
--- a/compass/landice/tests/ismip7_forcing/atmosphere/process_temperature.py
+++ b/compass/landice/tests/ismip7_forcing/atmosphere/process_temperature.py
@@ -7,7 +7,6 @@
 from mpas_tools.logging import check_call
 
 from compass.landice.ismip7.ice_sheet_params import get_params
-from compass.landice.ismip7.mapping import build_mapping_file
 from compass.landice.ismip7.remap import extrapolate_source
 from compass.step import Step
 
@@ -38,11 +37,22 @@ def setup(self):
         section = config["ismip7"]
         base_path_mali = section.get("base_path_mali")
         mali_mesh_file = section.get("mali_mesh_file")
+        mali_mesh_name = section.get("mali_mesh_name")
+        ice_sheet = section.get("ice_sheet")
+
+        section_atm = config["ismip7_atmosphere"]
+        method_remap = section_atm.get("method_remap")
 
         self.add_input_file(filename=mali_mesh_file,
                             target=os.path.join(base_path_mali,
                                                 mali_mesh_file))
 
+        # Add input file for the mapping file from build_mapping_file step
+        mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
+                        f"{mali_mesh_name}_{method_remap}.nc")
+        self.add_input_file(filename=mapping_file,
+                            target=f"../build_mapping_file/{mapping_file}")
+
     def run(self):
         """
         Run this step of the test case
@@ -54,7 +64,6 @@ def run(self):
         section = config["ismip7"]
         base_path_ismip7 = section.get("base_path_ismip7")
         mali_mesh_name = section.get("mali_mesh_name")
-        mali_mesh_file = section.get("mali_mesh_file")
         model = section.get("model")
         scenario = section.get("scenario")
         output_base_path = section.get("output_base_path")
@@ -102,18 +111,12 @@ def run(self):
         logger.info(f"Found {len(input_files)} temperature files for years "
                     f"{start_year}-{end_year}")
 
-        # Build mapping file (reuse if already created by process_smb)
+        # Construct the mapping file name (symlinked from
+        # build_mapping_file step)
         ice_sheet = config.get("ismip7", "ice_sheet")
         mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
                         f"{mali_mesh_name}_{method_remap}.nc")
 
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file...")
-            build_mapping_file(config, logger,
-                               input_files[0], mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
-
         # Remap each year file
         remapped_files = []
         for input_file in input_files:
diff --git a/compass/landice/tests/ismip7_forcing/atmosphere/process_temperature_gradient.py b/compass/landice/tests/ismip7_forcing/atmosphere/process_temperature_gradient.py
index 41cf9f30aa..add1090a9b 100644
--- a/compass/landice/tests/ismip7_forcing/atmosphere/process_temperature_gradient.py
+++ b/compass/landice/tests/ismip7_forcing/atmosphere/process_temperature_gradient.py
@@ -7,7 +7,6 @@
 from mpas_tools.logging import check_call
 
 from compass.landice.ismip7.ice_sheet_params import get_params
-from compass.landice.ismip7.mapping import build_mapping_file
 from compass.landice.ismip7.remap import extrapolate_source
 from compass.step import Step
 
@@ -40,11 +39,22 @@ def setup(self):
         section = config["ismip7"]
         base_path_mali = section.get("base_path_mali")
         mali_mesh_file = section.get("mali_mesh_file")
+        mali_mesh_name = section.get("mali_mesh_name")
+        ice_sheet = section.get("ice_sheet")
+
+        section_atm = config["ismip7_atmosphere"]
+        method_remap = section_atm.get("method_remap")
 
         self.add_input_file(filename=mali_mesh_file,
                             target=os.path.join(base_path_mali,
                                                 mali_mesh_file))
 
+        # Add input file for the mapping file from build_mapping_file step
+        mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
+                        f"{mali_mesh_name}_{method_remap}.nc")
+        self.add_input_file(filename=mapping_file,
+                            target=f"../build_mapping_file/{mapping_file}")
+
     def run(self):
         """
         Run this step of the test case
@@ -56,7 +66,6 @@ def run(self):
         section = config["ismip7"]
         base_path_ismip7 = section.get("base_path_ismip7")
         mali_mesh_name = section.get("mali_mesh_name")
-        mali_mesh_file = section.get("mali_mesh_file")
         model = section.get("model")
         scenario = section.get("scenario")
         output_base_path = section.get("output_base_path")
@@ -104,18 +113,12 @@ def run(self):
         logger.info(f"Found {len(input_files)} temperature gradient files "
                     f"for years {start_year}-{end_year}")
 
-        # Build mapping file (reuse if already created by other steps)
+        # Construct the mapping file name (symlinked from
+        # build_mapping_file step)
         ice_sheet = config.get("ismip7", "ice_sheet")
         mapping_file = (f"map_ismip7_{ice_sheet}_atm_to_"
                         f"{mali_mesh_name}_{method_remap}.nc")
 
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file...")
-            build_mapping_file(config, logger,
-                               input_files[0], mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
-
         # Remap each year file
         remapped_files = []
         for input_file in input_files:
diff --git a/compass/landice/tests/ismip7_forcing/fracture/__init__.py b/compass/landice/tests/ismip7_forcing/fracture/__init__.py
index b6a7e63c6a..ba34980e6a 100644
--- a/compass/landice/tests/ismip7_forcing/fracture/__init__.py
+++ b/compass/landice/tests/ismip7_forcing/fracture/__init__.py
@@ -1,6 +1,9 @@
 from compass.landice.tests.ismip7_forcing.configure import (
     configure as configure_testgroup,
 )
+from compass.landice.tests.ismip7_forcing.fracture.build_mapping_file import (
+    BuildMappingFile,
+)
 from compass.landice.tests.ismip7_forcing.fracture.process_excess_melt import (
     ProcessExcessMelt,
 )
@@ -40,6 +43,7 @@ def __init__(self, test_group):
         subdir = name
         super().__init__(test_group=test_group, name=name, subdir=subdir)
 
+        self.add_step(BuildMappingFile(test_case=self))
         self.add_step(ProcessExcessMelt(test_case=self))
         self.add_step(ProcessLakeProperties(test_case=self))
         self.add_step(ProcessShelfCollapse(test_case=self))
diff --git a/compass/landice/tests/ismip7_forcing/fracture/build_mapping_file.py b/compass/landice/tests/ismip7_forcing/fracture/build_mapping_file.py
new file mode 100644
index 0000000000..17a68ac529
--- /dev/null
+++ b/compass/landice/tests/ismip7_forcing/fracture/build_mapping_file.py
@@ -0,0 +1,142 @@
+import glob
+import os
+import shutil
+
+from compass.landice.ismip7.mapping import build_mapping_file
+from compass.step import Step
+
+
+class BuildMappingFile(Step):
+    """
+    A step for building ESMF mapping files (regridding weights) from the
+    ISMIP7 fracture grid to the MALI mesh. This step runs ESMF_RegridWeightGen
+    with the full esmf_ntasks allocation, so it can be run on a separate node
+    allocation from the processing steps (which run on a single node).
+
+    Up to three mapping files may be built, one for each enabled fracture
+    pathway (shelf collapse, excess melt, lake properties), since each may
+    use a different remapping method. The mapping files can be reused across
+    scenarios. If mapping_files_path is provided in the config, this step will
+    symlink any existing weight files from that directory and skip building
+    those that already exist.
+    """
+
+    def __init__(self, test_case):
+        """
+        Create the step
+
+        Parameters
+        ----------
+        test_case : compass.landice.tests.ismip7_forcing.fracture.Fracture
+            The test case this step belongs to
+        """
+        super().__init__(test_case=test_case, name="build_mapping_file")
+
+    def setup(self):
+        """
+        Set up this step of the test case
+        """
+        config = self.config
+        section = config["ismip7"]
+        base_path_mali = section.get("base_path_mali")
+        mali_mesh_file = section.get("mali_mesh_file")
+
+        self.add_input_file(filename=mali_mesh_file,
+                            target=os.path.join(base_path_mali,
+                                                mali_mesh_file))
+
+        # Request the full esmf_ntasks allocation for this step
+        self.ntasks = section.getint("esmf_ntasks")
+        self.min_tasks = self.ntasks
+
+    def run(self):
+        """
+        Run this step of the test case
+        """
+        logger = self.logger
+        config = self.config
+
+        section = config["ismip7"]
+        base_path_ismip7 = section.get("base_path_ismip7")
+        mali_mesh_name = section.get("mali_mesh_name")
+        mali_mesh_file = section.get("mali_mesh_file")
+        ice_sheet = section.get("ice_sheet")
+        output_base_path = section.get("output_base_path")
+
+        # Check if user provided a path to reuse existing weight files
+        mapping_files_path = section.get("mapping_files_path")
+
+        section = config["ismip7_fracture"]
+        version = section.get("version")
+
+        # Three fracture pathways, each with its own remapping method
+        fracture_paths = [
+            ("shelf_collapse", "method_remap_shelf_collapse",
+             "ice_shelf_collapse_mask_*.nc"),
+            ("excess_melt", "method_remap_excess_melt",
+             "excess_meltwaterinput_*.nc"),
+            ("lake_properties", "method_remap_lake_properties",
+             "lake_properties_*.nc"),
+        ]
+
+        # Build a mapping file for each enabled pathway
+        for pathway_name, method_key, file_pattern in fracture_paths:
+            method_remap = section.get(method_key)
+
+            # Skip if method is None
+            if method_remap.lower() == "none":
+                logger.info(f"{method_key} is None; skipping {pathway_name} "
+                            f"mapping file.")
+                continue
+
+            # Construct the canonical mapping file name
+            mapping_file = (f"map_ismip7_{ice_sheet}_fracture_to_"
+                            f"{mali_mesh_name}_{method_remap}.nc")
+
+            # If mapping_files_path is provided, symlink any existing file
+            if mapping_files_path != "NotAvailable":
+                source_file = os.path.join(mapping_files_path, mapping_file)
+                if os.path.exists(source_file):
+                    logger.info(f"Symlinking existing mapping file for "
+                                f"{pathway_name} from {mapping_files_path}")
+                    if os.path.exists(mapping_file):
+                        os.remove(mapping_file)
+                    os.symlink(source_file, mapping_file)
+
+            # Use the pathway's fracture file as the grid template
+            input_path = os.path.join(base_path_ismip7, "fracture", version)
+            grid_files = sorted(
+                glob.glob(os.path.join(input_path, file_pattern)))
+            if not grid_files:
+                raise FileNotFoundError(
+                    f"No {pathway_name} file found matching pattern:\n"
+                    f"  {os.path.join(input_path, file_pattern)}")
+
+            ismip7_grid_file = grid_files[0]
+            logger.info(f"Building {pathway_name} mapping file using grid "
+                        f"template: {os.path.basename(ismip7_grid_file)}")
+
+            # Build the mapping file (build_mapping_file will skip if it
+            # already exists, e.g., from the symlink above or a previous
+            # failed run)
+            build_mapping_file(config, logger, ismip7_grid_file, mapping_file,
+                               mali_mesh_file=mali_mesh_file,
+                               method_remap=method_remap)
+
+            # Copy the mapping file to output_base_path/mapping_files/ for
+            # reuse in future runs
+            mapping_files_dir = os.path.join(output_base_path, "mapping_files")
+            if not os.path.exists(mapping_files_dir):
+                os.makedirs(mapping_files_dir)
+
+            dst = os.path.join(mapping_files_dir, mapping_file)
+            # Only copy if it's a real file (not a symlink we just created)
+            if not os.path.islink(mapping_file):
+                logger.info(f"Copying {pathway_name} mapping file to "
+                            f"{mapping_files_dir} for reuse")
+                shutil.copy(mapping_file, dst)
+            else:
+                logger.info(f"{pathway_name} mapping file is a symlink; not "
+                            f"copying to {mapping_files_dir}")
+
+        logger.info("Done building fracture mapping files.")
diff --git a/compass/landice/tests/ismip7_forcing/fracture/process_excess_melt.py b/compass/landice/tests/ismip7_forcing/fracture/process_excess_melt.py
index 0f291792f0..2c432158bc 100644
--- a/compass/landice/tests/ismip7_forcing/fracture/process_excess_melt.py
+++ b/compass/landice/tests/ismip7_forcing/fracture/process_excess_melt.py
@@ -7,7 +7,6 @@
 from mpas_tools.io import write_netcdf
 from mpas_tools.logging import check_call
 
-from compass.landice.ismip7.mapping import build_mapping_file
 from compass.landice.ismip7.remap import (
     add_xtime_and_write,
     extrapolate_source,
@@ -49,11 +48,24 @@ def setup(self):
         section = config["ismip7"]
         base_path_mali = section.get("base_path_mali")
         mali_mesh_file = section.get("mali_mesh_file")
+        mali_mesh_name = section.get("mali_mesh_name")
+        ice_sheet = section.get("ice_sheet")
+
+        section_frac = config["ismip7_fracture"]
+        method_remap = section_frac.get("method_remap_excess_melt")
 
         self.add_input_file(filename=mali_mesh_file,
                             target=os.path.join(base_path_mali,
                                                 mali_mesh_file))
 
+        # Add input file for the mapping file from build_mapping_file step
+        # (only if method is not None)
+        if method_remap.lower() != "none":
+            mapping_file = (f"map_ismip7_{ice_sheet}_fracture_to_"
+                            f"{mali_mesh_name}_{method_remap}.nc")
+            self.add_input_file(filename=mapping_file,
+                                target=f"../build_mapping_file/{mapping_file}")
+
     def run(self):
         """
         Run this step of the test case
@@ -64,7 +76,6 @@ def run(self):
         section = config["ismip7"]
         base_path_ismip7 = section.get("base_path_ismip7")
         mali_mesh_name = section.get("mali_mesh_name")
-        mali_mesh_file = section.get("mali_mesh_file")
         model = section.get("model")
         scenario = section.get("scenario")
         output_base_path = section.get("output_base_path")
@@ -105,18 +116,10 @@ def run(self):
         self._prepare_source_grid(input_file, input_path, gridded_file,
                                   logger)
 
-        # Build mapping file. Excess melt is a flux, so conservative
-        # remapping is appropriate by default.
+        # Construct mapping file name (symlinked from build_mapping_file step)
         mapping_file = (f"map_ismip7_{ice_sheet}_fracture_to_"
                         f"{mali_mesh_name}_{method_remap}.nc")
 
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file for the excess melt grid...")
-            build_mapping_file(config, logger,
-                               gridded_file, mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
-
         # Extrapolate fill values on the source grid before remapping so
         # they don't pollute neighboring cells during interpolation
         extrap_file = f"extrap_{basename}"
diff --git a/compass/landice/tests/ismip7_forcing/fracture/process_lake_properties.py b/compass/landice/tests/ismip7_forcing/fracture/process_lake_properties.py
index 2b5d5ac1d5..e6cc092abf 100644
--- a/compass/landice/tests/ismip7_forcing/fracture/process_lake_properties.py
+++ b/compass/landice/tests/ismip7_forcing/fracture/process_lake_properties.py
@@ -4,7 +4,6 @@
 
 from mpas_tools.logging import check_call
 
-from compass.landice.ismip7.mapping import build_mapping_file
 from compass.landice.ismip7.remap import (
     add_xtime_and_write,
     extrapolate_source,
@@ -54,11 +53,24 @@ def setup(self):
         section = config["ismip7"]
         base_path_mali = section.get("base_path_mali")
         mali_mesh_file = section.get("mali_mesh_file")
+        mali_mesh_name = section.get("mali_mesh_name")
+        ice_sheet = section.get("ice_sheet")
+
+        section_frac = config["ismip7_fracture"]
+        method_remap = section_frac.get("method_remap_lake_properties")
 
         self.add_input_file(filename=mali_mesh_file,
                             target=os.path.join(base_path_mali,
                                                 mali_mesh_file))
 
+        # Add input file for the mapping file from build_mapping_file step
+        # (only if method is not None)
+        if method_remap.lower() != "none":
+            mapping_file = (f"map_ismip7_{ice_sheet}_fracture_to_"
+                            f"{mali_mesh_name}_{method_remap}.nc")
+            self.add_input_file(filename=mapping_file,
+                                target=f"../build_mapping_file/{mapping_file}")
+
     def run(self):
         """
         Run this step of the test case
@@ -69,7 +81,6 @@ def run(self):
         section = config["ismip7"]
         base_path_ismip7 = section.get("base_path_ismip7")
         mali_mesh_name = section.get("mali_mesh_name")
-        mali_mesh_file = section.get("mali_mesh_file")
         model = section.get("model")
         scenario = section.get("scenario")
         output_base_path = section.get("output_base_path")
@@ -105,19 +116,10 @@ def run(self):
         basename = os.path.basename(input_file)
         logger.info(f"Processing lake properties: {basename}")
 
-        # Build mapping file. Lake properties are continuous fields, so
-        # bilinear remapping is appropriate by default.
+        # Construct mapping file name (symlinked from build_mapping_file step)
         mapping_file = (f"map_ismip7_{ice_sheet}_fracture_to_"
                         f"{mali_mesh_name}_{method_remap}.nc")
 
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file for the lake properties "
-                        "grid...")
-            build_mapping_file(config, logger,
-                               input_file, mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
-
         # Extrapolate fill values on the source grid before remapping so
         # they don't pollute neighboring cells during interpolation
         extrap_file = f"extrap_{basename}"
diff --git a/compass/landice/tests/ismip7_forcing/fracture/process_shelf_collapse.py b/compass/landice/tests/ismip7_forcing/fracture/process_shelf_collapse.py
index bf6537438e..f4c0b67ba9 100644
--- a/compass/landice/tests/ismip7_forcing/fracture/process_shelf_collapse.py
+++ b/compass/landice/tests/ismip7_forcing/fracture/process_shelf_collapse.py
@@ -4,7 +4,6 @@
 
 from mpas_tools.logging import check_call
 
-from compass.landice.ismip7.mapping import build_mapping_file
 from compass.landice.ismip7.remap import (
     add_xtime_and_write,
     open_rename_and_trim,
@@ -41,11 +40,24 @@ def setup(self):
         section = config["ismip7"]
         base_path_mali = section.get("base_path_mali")
         mali_mesh_file = section.get("mali_mesh_file")
+        mali_mesh_name = section.get("mali_mesh_name")
+        ice_sheet = section.get("ice_sheet")
+
+        section_frac = config["ismip7_fracture"]
+        method_remap = section_frac.get("method_remap_shelf_collapse")
 
         self.add_input_file(filename=mali_mesh_file,
                             target=os.path.join(base_path_mali,
                                                 mali_mesh_file))
 
+        # Add input file for the mapping file from build_mapping_file step
+        # (only if method is not None)
+        if method_remap.lower() != "none":
+            mapping_file = (f"map_ismip7_{ice_sheet}_fracture_to_"
+                            f"{mali_mesh_name}_{method_remap}.nc")
+            self.add_input_file(filename=mapping_file,
+                                target=f"../build_mapping_file/{mapping_file}")
+
     def run(self):
         """
         Run this step of the test case
@@ -56,7 +68,6 @@ def run(self):
         section = config["ismip7"]
         base_path_ismip7 = section.get("base_path_ismip7")
         mali_mesh_name = section.get("mali_mesh_name")
-        mali_mesh_file = section.get("mali_mesh_file")
         model = section.get("model")
         scenario = section.get("scenario")
         output_base_path = section.get("output_base_path")
@@ -92,17 +103,10 @@ def run(self):
         basename = os.path.basename(input_file)
         logger.info(f"Processing ice shelf collapse mask: {basename}")
 
-        # Build mapping file. neareststod preserves the 0/1 mask values.
+        # Construct mapping file name (symlinked from build_mapping_file step)
         mapping_file = (f"map_ismip7_{ice_sheet}_fracture_to_"
                         f"{mali_mesh_name}_{method_remap}.nc")
 
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file for the collapse mask grid...")
-            build_mapping_file(config, logger,
-                               input_file, mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
-
         # Remap the collapse mask onto the MALI mesh
         remapped_file = f"remapped_{basename}"
         if not os.path.exists(remapped_file):
diff --git a/compass/landice/tests/ismip7_forcing/ismip7_forcing.cfg b/compass/landice/tests/ismip7_forcing/ismip7_forcing.cfg
index be7d195aa4..e2104c4f6a 100644
--- a/compass/landice/tests/ismip7_forcing/ismip7_forcing.cfg
+++ b/compass/landice/tests/ismip7_forcing/ismip7_forcing.cfg
@@ -30,6 +30,13 @@ mali_mesh_file = NotAvailable
 # Number of MPI tasks for ESMF_RegridWeightGen
 esmf_ntasks = 128
 
+# Optional path to a directory of pre-built mapping files for reuse across runs.
+# If provided, the test case will symlink any existing, canonically-named weight
+# files from this directory and build only the missing ones. To reuse weights from
+# a previous run, point this at <prior_output_base_path>/mapping_files/.
+# If not provided or set to NotAvailable, all weight files are built from scratch.
+mapping_files_path = NotAvailable
+
 # Whether to process time-varying ocean thermal forcing (ESM scenario data)
 process_ocean_thermal = true
 
diff --git a/compass/landice/tests/ismip7_forcing/ismip7_forcing_ocx_ais.cfg b/compass/landice/tests/ismip7_forcing/ismip7_forcing_ocx_ais.cfg
index 975cb89b85..43d4efaa52 100644
--- a/compass/landice/tests/ismip7_forcing/ismip7_forcing_ocx_ais.cfg
+++ b/compass/landice/tests/ismip7_forcing/ismip7_forcing_ocx_ais.cfg
@@ -39,6 +39,13 @@ mali_mesh_file = AIS_4to20km_r01_20220907.nc
 # Number of MPI tasks for ESMF_RegridWeightGen
 esmf_ntasks = 512
 
+# Optional path to a directory of pre-built mapping files for reuse across runs.
+# If provided, the test case will symlink any existing, canonically-named weight
+# files from this directory and build only the missing ones. To reuse weights from
+# a previous run, point this at <prior_output_base_path>/mapping_files/.
+# If not provided or set to NotAvailable, all weight files are built from scratch.
+mapping_files_path = NotAvailable
+
 # Whether to process time-varying ocean thermal forcing (ESM scenario data)
 process_ocean_thermal = true
 
diff --git a/compass/landice/tests/ismip7_forcing/ismip7_forcing_ocx_gis.cfg b/compass/landice/tests/ismip7_forcing/ismip7_forcing_ocx_gis.cfg
index d3658027db..57df8aa2dd 100644
--- a/compass/landice/tests/ismip7_forcing/ismip7_forcing_ocx_gis.cfg
+++ b/compass/landice/tests/ismip7_forcing/ismip7_forcing_ocx_gis.cfg
@@ -37,6 +37,13 @@ mali_mesh_file = GIS_1to10km_r02_20230202.nc
 # Number of MPI tasks for ESMF_RegridWeightGen
 esmf_ntasks = 512
 
+# Optional path to a directory of pre-built mapping files for reuse across runs.
+# If provided, the test case will symlink any existing, canonically-named weight
+# files from this directory and build only the missing ones. To reuse weights from
+# a previous run, point this at <prior_output_base_path>/mapping_files/.
+# If not provided or set to NotAvailable, all weight files are built from scratch.
+mapping_files_path = NotAvailable
+
 # Whether to process time-varying ocean thermal forcing (ESM scenario data)
 process_ocean_thermal = true
 
diff --git a/compass/landice/tests/ismip7_forcing/ismip7_forcing_test.cfg b/compass/landice/tests/ismip7_forcing/ismip7_forcing_test.cfg
index ab282b2e06..b5c795bf3d 100644
--- a/compass/landice/tests/ismip7_forcing/ismip7_forcing_test.cfg
+++ b/compass/landice/tests/ismip7_forcing/ismip7_forcing_test.cfg
@@ -30,6 +30,13 @@ mali_mesh_file = AIS_4to20km_r01_20220907.nc
 # Number of MPI tasks for ESMF_RegridWeightGen
 esmf_ntasks = 512
 
+# Optional path to a directory of pre-built mapping files for reuse across runs.
+# If provided, the test case will symlink any existing, canonically-named weight
+# files from this directory and build only the missing ones. To reuse weights from
+# a previous run, point this at <prior_output_base_path>/mapping_files/.
+# If not provided or set to NotAvailable, all weight files are built from scratch.
+mapping_files_path = NotAvailable
+
 # Whether to process time-varying ocean thermal forcing (ESM scenario data)
 process_ocean_thermal = false
 
diff --git a/compass/landice/tests/ismip7_forcing/ocean_thermal/__init__.py b/compass/landice/tests/ismip7_forcing/ocean_thermal/__init__.py
index 2a97700428..e384db2cb4 100644
--- a/compass/landice/tests/ismip7_forcing/ocean_thermal/__init__.py
+++ b/compass/landice/tests/ismip7_forcing/ocean_thermal/__init__.py
@@ -1,6 +1,9 @@
 from compass.landice.tests.ismip7_forcing.configure import (
     configure as configure_testgroup,
 )
+from compass.landice.tests.ismip7_forcing.ocean_thermal.build_mapping_file import (  # noqa: E501
+    BuildMappingFile,
+)
 from compass.landice.tests.ismip7_forcing.ocean_thermal.process_thermal_forcing import (  # noqa: E501
     ProcessThermalForcing,
 )
@@ -29,6 +32,7 @@ def __init__(self, test_group):
         subdir = name
         super().__init__(test_group=test_group, name=name, subdir=subdir)
 
+        self.add_step(BuildMappingFile(test_case=self))
         self.add_step(ProcessThermalForcing(test_case=self))
 
     def configure(self):
diff --git a/compass/landice/tests/ismip7_forcing/ocean_thermal/build_mapping_file.py b/compass/landice/tests/ismip7_forcing/ocean_thermal/build_mapping_file.py
new file mode 100644
index 0000000000..9682bd70a8
--- /dev/null
+++ b/compass/landice/tests/ismip7_forcing/ocean_thermal/build_mapping_file.py
@@ -0,0 +1,153 @@
+import glob
+import os
+import shutil
+
+from compass.landice.ismip7.ice_sheet_params import get_params
+from compass.landice.ismip7.mapping import build_mapping_file
+from compass.step import Step
+
+
+class BuildMappingFile(Step):
+    """
+    A step for building the ESMF mapping file (regridding weights) from the
+    ISMIP7 ocean grid to the MALI mesh. This step runs ESMF_RegridWeightGen
+    with the full esmf_ntasks allocation, so it can be run on a separate node
+    allocation from the processing steps (which run on a single node).
+
+    The mapping file can be reused across scenarios and ocean choices, since
+    it depends only on the ice sheet, mesh name, and remapping method. If
+    mapping_files_path is provided in the config, this step will symlink any
+    existing weight file from that directory and skip the build.
+    """
+
+    def __init__(self, test_case):
+        """
+        Create the step
+
+        Parameters
+        ----------
+        test_case : compass.landice.tests.ismip7_forcing.ocean_thermal.\
+OceanThermal
+            The test case this step belongs to
+        """
+        super().__init__(test_case=test_case, name="build_mapping_file")
+
+    def setup(self):
+        """
+        Set up this step of the test case
+        """
+        config = self.config
+        section = config["ismip7"]
+        base_path_mali = section.get("base_path_mali")
+        mali_mesh_file = section.get("mali_mesh_file")
+
+        self.add_input_file(filename=mali_mesh_file,
+                            target=os.path.join(base_path_mali,
+                                                mali_mesh_file))
+
+        # Request the full esmf_ntasks allocation for this step
+        self.ntasks = section.getint("esmf_ntasks")
+        self.min_tasks = self.ntasks
+
+    def run(self):
+        """
+        Run this step of the test case
+        """
+        logger = self.logger
+        config = self.config
+        params = get_params(config)
+
+        section = config["ismip7"]
+        base_path_ismip7 = section.get("base_path_ismip7")
+        mali_mesh_name = section.get("mali_mesh_name")
+        mali_mesh_file = section.get("mali_mesh_file")
+        ice_sheet = section.get("ice_sheet")
+        output_base_path = section.get("output_base_path")
+        model = section.get("model")
+        scenario = section.get("scenario")
+
+        # Check if user provided a path to reuse existing weight files
+        mapping_files_path = section.get("mapping_files_path")
+
+        section = config["ismip7_ocean_thermal"]
+        method_remap = section.get("method_remap")
+
+        # Construct the canonical mapping file name
+        mapping_file = (f"map_ismip7_{ice_sheet}_ocean_to_"
+                        f"{mali_mesh_name}_{method_remap}.nc")
+
+        # If mapping_files_path is provided, symlink any existing file
+        if mapping_files_path != "NotAvailable":
+            source_file = os.path.join(mapping_files_path, mapping_file)
+            if os.path.exists(source_file):
+                logger.info(f"Symlinking existing mapping file from "
+                            f"{mapping_files_path}")
+                if os.path.exists(mapping_file):
+                    os.remove(mapping_file)
+                os.symlink(source_file, mapping_file)
+
+        # Use any ocean thermal forcing file as the grid template for building
+        # the mapping file. Look for the first available thermal_forcing file.
+        prefix = params['prefix']
+        version = params['ocean_version']
+        ocean_grid = params['ocean_grid']
+
+        # For OCX scenarios, the directory structure differs
+        if params.get('ocean_choice_layout', False):
+            # AIS OCX: files are in subdirectories (main/cold/warm/vary)
+            # Use 'main' as the default choice for building the mapping file
+            ocean_choice = 'main'
+            input_path = os.path.join(
+                base_path_ismip7, "ocean", ocean_choice, version)
+            file_pattern = (f"tf_{prefix}_OCX_{ocean_grid}_{ocean_choice}_"
+                            f"{version}_*.nc")
+        else:
+            # Standard ESM scenario or GrIS OCX
+            if params['ocean_model'] is not None:
+                # OCX (GrIS): use the ocean_model token
+                ocean_model = params['ocean_model']
+                input_path = os.path.join(
+                    base_path_ismip7, "ocean", "tf", version)
+                file_pattern = (f"tf_{prefix}_{ocean_model}_"
+                                f"{ocean_grid}_{version}_*.nc")
+            else:
+                # Standard ESM scenario
+                input_path = os.path.join(
+                    base_path_ismip7, "ocean", version)
+                file_pattern = (f"tf_{prefix}_{model}_"
+                                f"{scenario}_{ocean_grid}_{version}_*.nc")
+
+        ismip7_grid_files = sorted(
+            glob.glob(os.path.join(input_path, file_pattern)))
+        if not ismip7_grid_files:
+            raise FileNotFoundError(
+                f"No ocean thermal forcing file found matching pattern:\n"
+                f"  {os.path.join(input_path, file_pattern)}")
+
+        ismip7_grid_file = ismip7_grid_files[0]
+        logger.info(f"Using grid template: "
+                    f"{os.path.basename(ismip7_grid_file)}")
+
+        # Build the mapping file (build_mapping_file will skip if it already
+        # exists, e.g., from the symlink above or a previous failed run)
+        build_mapping_file(config, logger, ismip7_grid_file, mapping_file,
+                           mali_mesh_file=mali_mesh_file,
+                           method_remap=method_remap)
+
+        # Copy the mapping file to output_base_path/mapping_files/ for reuse
+        # in future runs
+        mapping_files_dir = os.path.join(output_base_path, "mapping_files")
+        if not os.path.exists(mapping_files_dir):
+            os.makedirs(mapping_files_dir)
+
+        dst = os.path.join(mapping_files_dir, mapping_file)
+        # Only copy if it's a real file (not a symlink we just created)
+        if not os.path.islink(mapping_file):
+            logger.info(f"Copying mapping file to {mapping_files_dir} "
+                        f"for reuse")
+            shutil.copy(mapping_file, dst)
+        else:
+            logger.info(f"Mapping file is a symlink; not copying to "
+                        f"{mapping_files_dir}")
+
+        logger.info("Done building ocean mapping file.")
diff --git a/compass/landice/tests/ismip7_forcing/ocean_thermal/process_thermal_forcing.py b/compass/landice/tests/ismip7_forcing/ocean_thermal/process_thermal_forcing.py
index 595d90b964..cac23903cf 100644
--- a/compass/landice/tests/ismip7_forcing/ocean_thermal/process_thermal_forcing.py
+++ b/compass/landice/tests/ismip7_forcing/ocean_thermal/process_thermal_forcing.py
@@ -7,7 +7,6 @@
 from mpas_tools.logging import check_call
 
 from compass.landice.ismip7.ice_sheet_params import get_params
-from compass.landice.ismip7.mapping import build_mapping_file
 from compass.landice.ismip7.remap import extrapolate_source
 from compass.step import Step
 
@@ -42,11 +41,22 @@ def setup(self):
         section = config["ismip7"]
         base_path_mali = section.get("base_path_mali")
         mali_mesh_file = section.get("mali_mesh_file")
+        mali_mesh_name = section.get("mali_mesh_name")
+        ice_sheet = section.get("ice_sheet")
+
+        section_ocean = config["ismip7_ocean_thermal"]
+        method_remap = section_ocean.get("method_remap")
 
         self.add_input_file(filename=mali_mesh_file,
                             target=os.path.join(base_path_mali,
                                                 mali_mesh_file))
 
+        # Add input file for the mapping file from build_mapping_file step
+        mapping_file = (f"map_ismip7_{ice_sheet}_ocean_to_"
+                        f"{mali_mesh_name}_{method_remap}.nc")
+        self.add_input_file(filename=mapping_file,
+                            target=f"../build_mapping_file/{mapping_file}")
+
     def run(self):
         """
         Run this step of the test case
@@ -249,7 +259,6 @@ def _process_ocean_forcing(self, job, mapping_file, ocean_3d,
             Base path under which output is written
         """
         logger = self.logger
-        config = self.config
 
         input_path = job['input_path']
         file_pattern = job['file_pattern']
@@ -284,13 +293,7 @@ def _process_ocean_forcing(self, job, mapping_file, ocean_3d,
         logger.info(f"Found {len(input_files)} ocean thermal forcing files "
                     f"overlapping years {start_year}-{end_year}")
 
-        # Build mapping file using the first input file as grid template.
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file for ocean grid...")
-            build_mapping_file(config, logger,
-                               input_files[0], mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
+        # Mapping file is symlinked from build_mapping_file step
 
         # Remap each file
         remapped_files = []
@@ -362,7 +365,6 @@ def _run_climatology(self):
 
         section = config["ismip7"]
         mali_mesh_name = section.get("mali_mesh_name")
-        mali_mesh_file = section.get("mali_mesh_file")
         output_base_path = section.get("output_base_path")
         ice_sheet = section.get("ice_sheet")
 
@@ -385,17 +387,10 @@ def _run_climatology(self):
         logger.info(f"Processing ocean TF climatology: "
                     f"{os.path.basename(input_file)}")
 
-        # Build mapping file using the climatology file as grid template.
+        # Construct mapping file name (symlinked from build_mapping_file step)
         mapping_file = (f"map_ismip7_{ice_sheet}_ocean_to_"
                         f"{mali_mesh_name}_{method_remap}.nc")
 
-        if not os.path.exists(mapping_file):
-            logger.info("Building mapping file for ocean grid...")
-            build_mapping_file(config, logger,
-                               input_file, mapping_file,
-                               mali_mesh_file=mali_mesh_file,
-                               method_remap=method_remap)
-
         # Extrapolate and remap
         basename = os.path.basename(input_file)
         remapped_file = f"remapped_{basename}"
diff --git a/docs/developers_guide/landice/test_groups/ismip7_forcing.rst b/docs/developers_guide/landice/test_groups/ismip7_forcing.rst
index 6f88904b99..fa3b6c2e5b 100644
--- a/docs/developers_guide/landice/test_groups/ismip7_forcing.rst
+++ b/docs/developers_guide/landice/test_groups/ismip7_forcing.rst
@@ -26,7 +26,8 @@ package :py:mod:`compass.landice.ismip7`, described in
 ice-sheet-specific parameters (projection, file naming prefix, grid
 resolution, data version, ocean dimensionality),
 :py:func:`compass.landice.ismip7.mapping.build_mapping_file` to create the
-SCRIP and ESMF mapping files, and the remapping helpers in
+SCRIP and ESMF mapping files (called from ``BuildMappingFile`` steps, not from
+processing steps), and the remapping helpers in
 :py:mod:`compass.landice.ismip7.remap`.
 
 When ``scenario = OCX``, ``get_params`` applies a set of OCX overrides on top
@@ -61,14 +62,28 @@ atmosphere
 ~~~~~~~~~~
 
 The :py:class:`compass.landice.tests.ismip7_forcing.atmosphere.Atmosphere`
-test case processes the ISMIP7 atmosphere forcing fields. It contains five
-steps: SMB, temperature, their respective gradients, and runoff. Each step
-discovers input files matching the ice-sheet-specific naming pattern, builds
-or reuses a mapping file, remaps each input file with ``ncremap``, and
-combines/renames the results to MALI conventions.
+test case processes the ISMIP7 atmosphere forcing fields. It contains six
+steps: a weight-generation step followed by five processing steps (SMB,
+temperature, their respective gradients, and runoff).
+
+The weight-generation step runs ``ESMF_RegridWeightGen`` with ``esmf_ntasks``
+MPI tasks to build regridding weights from the ISMIP7 atmosphere grid to the
+MALI mesh. All five processing steps consume the same mapping file (all
+atmosphere variables share the same source grid).
+
+Each processing step discovers input files matching the ice-sheet-specific
+naming pattern, remaps each input file with ``ncremap`` using the pre-built
+mapping file, and combines/renames the results to MALI conventions. Processing
+steps run at ``ntasks=1`` (single node).
 
 Steps:
 
+* :py:class:`~compass.landice.tests.ismip7_forcing.atmosphere.build_mapping_file.BuildMappingFile` —
+  Builds one shared mapping file for all atmosphere variables. The file is
+  copied to ``<output_base_path>/mapping_files/`` for reuse across scenarios.
+  If ``mapping_files_path`` is provided in the config, symlinks any existing
+  weight file from that directory and skips the build.
+
 * :py:class:`~compass.landice.tests.ismip7_forcing.atmosphere.process_smb.ProcessSmb` —
   ``acabf`` → ``sfcMassBal``
 * :py:class:`~compass.landice.tests.ismip7_forcing.atmosphere.process_temperature.ProcessTemperature` —
@@ -86,20 +101,39 @@ ocean_thermal
 ~~~~~~~~~~~~~
 
 The :py:class:`compass.landice.tests.ismip7_forcing.ocean_thermal.OceanThermal`
-test case processes the ISMIP7 ocean thermal forcing. It contains a single step,
+test case processes the ISMIP7 ocean thermal forcing. It contains two steps: a
+weight-generation step followed by the processing step.
+
+The weight-generation step runs ``ESMF_RegridWeightGen`` with ``esmf_ntasks``
+MPI tasks to build regridding weights from the ISMIP7 ocean grid to the MALI
+mesh. One mapping file is built and shared across scenario and climatology
+processing (if both are enabled and use the same remapping method).
+
+The processing step,
 :py:class:`~compass.landice.tests.ismip7_forcing.ocean_thermal.process_thermal_forcing.ProcessThermalForcing`,
-which handles both AIS (3D, decade-spanning files) and GrIS (2D, yearly files)
-by branching on the ``ocean_3d`` parameter from ``ice_sheet_params``.
+handles both AIS (3D, decade-spanning files) and GrIS (2D, yearly files) by
+branching on the ``ocean_3d`` parameter from ``ice_sheet_params``. It runs at
+``ntasks=1`` (single node).
 
-The ``run()`` method dispatches to two sub-methods based on the boolean config
-options ``process_ocean_thermal`` and ``process_ocean_climatology`` in the
-``[ismip7]`` section:
+Steps:
+
+* :py:class:`~compass.landice.tests.ismip7_forcing.ocean_thermal.build_mapping_file.BuildMappingFile` —
+  Builds one mapping file for ocean thermal forcing (shared across scenario and
+  climatology if methods match). The file is copied to
+  ``<output_base_path>/mapping_files/`` for reuse across scenarios. If
+  ``mapping_files_path`` is provided in the config, symlinks any existing
+  weight file from that directory and skips the build.
 
-* ``_run_scenario()``: Processes time-varying ESM scenario data (model +
-  scenario combination). Uses config from ``[ismip7_ocean_thermal]``.
-* ``_run_climatology()``: Processes the static observational climatology
-  (Zhou et al., AIS only). Uses config from ``[ismip7_ocean_climatology]``.
-  The TF version (currently v3) is hard-coded.
+* :py:class:`~compass.landice.tests.ismip7_forcing.ocean_thermal.process_thermal_forcing.ProcessThermalForcing` —
+  The ``run()`` method dispatches to two sub-methods based on the boolean
+  config options ``process_ocean_thermal`` and ``process_ocean_climatology`` in
+  the ``[ismip7]`` section:
+
+  * ``_run_scenario()``: Processes time-varying ESM scenario data (model +
+    scenario combination). Uses config from ``[ismip7_ocean_thermal]``.
+  * ``_run_climatology()``: Processes the static observational climatology
+    (Zhou et al., AIS only). Uses config from ``[ismip7_ocean_climatology]``.
+    The TF version (currently v3) is hard-coded.
 
 For AIS scenario data, the step:
 
@@ -127,17 +161,32 @@ fracture
 
 The :py:class:`compass.landice.tests.ismip7_forcing.fracture.Fracture`
 test case processes the ISMIP7 surface-melt-driven ice shelf collapse
-forcing (AIS only). It implements the three ISMIP7 pathways as independent
-steps, each discovering its source file from the ``fracture/{version}/``
-subdirectory of ``base_path_ismip7``, building or reusing a mapping file,
-remapping with ``ncremap``, and renaming the result to MALI conventions with
-an accompanying ``xtime`` variable. Per-pathway remapping methods are set in
-the ``[ismip7_fracture]`` config section. Setting a pathway's remapping-method
-option to ``None`` causes that step to return early without processing its
-file, which is useful when only some pathway source files are available.
+forcing (AIS only). It contains four steps: a weight-generation step followed
+by three pathway processing steps.
+
+The weight-generation step runs ``ESMF_RegridWeightGen`` with ``esmf_ntasks``
+MPI tasks to build regridding weights from the ISMIP7 fracture grid to the
+MALI mesh. Up to three mapping files may be built (one per enabled pathway),
+depending on whether the pathways use different remapping methods.
+
+Each processing step discovers its source file from the ``fracture/{version}/``
+subdirectory of ``base_path_ismip7``, remaps with ``ncremap`` using the
+pre-built mapping file, and renames the result to MALI conventions with an
+accompanying ``xtime`` variable. Processing steps run at ``ntasks=1`` (single
+node). Per-pathway remapping methods are set in the ``[ismip7_fracture]``
+config section. Setting a pathway's remapping-method option to ``None`` causes
+that step to return early without processing its file, which is useful when
+only some pathway source files are available.
 
 Steps:
 
+* :py:class:`~compass.landice.tests.ismip7_forcing.fracture.build_mapping_file.BuildMappingFile` —
+  Builds up to three mapping files (one per enabled pathway with a non-None
+  remapping method). Files are copied to ``<output_base_path>/mapping_files/``
+  for reuse across scenarios. If ``mapping_files_path`` is provided in the
+  config, symlinks any existing weight files from that directory and builds
+  only the missing ones.
+
 * :py:class:`~compass.landice.tests.ismip7_forcing.fracture.process_excess_melt.ProcessExcessMelt`
   (Path A) — ``excess_melt`` → ``ismip7ExcessMelt``. The excess melt file
   lacks ``x``/``y`` coordinate variables and its array is flipped along the
diff --git a/docs/users_guide/landice/test_groups/ismip7_forcing.rst b/docs/users_guide/landice/test_groups/ismip7_forcing.rst
index 4a5ca9ea82..8e800e8862 100644
--- a/docs/users_guide/landice/test_groups/ismip7_forcing.rst
+++ b/docs/users_guide/landice/test_groups/ismip7_forcing.rst
@@ -11,20 +11,23 @@ The test group supports both the Antarctic Ice Sheet (AIS) and the Greenland
 Ice Sheet (GrIS), controlled by a single ``ice_sheet`` config option.
 
 The test group includes three test cases: ``atmosphere``, ``ocean_thermal``,
-and ``fracture``.
+and ``fracture``. Each test case begins with a ``build_mapping_file`` step that
+generates ESMF regridding weights, followed by processing steps that consume
+those weights to remap forcing data.
 
-* The ``atmosphere`` test case has five steps:
+* The ``atmosphere`` test case has six steps: ``build_mapping_file``,
   ``process_smb``, ``process_temperature``, ``process_smb_gradient``,
   ``process_temperature_gradient``, and ``process_runoff``.
 
-* The ``ocean_thermal`` test case has one step: ``process_thermal_forcing``.
-  For AIS this produces 3D thermal forcing (with 30 ocean depth layers); for
-  GrIS it produces 2D (depth-averaged) thermal forcing. The step can also
-  process the observational ocean thermal forcing climatology (Zhou et al.)
-  for AIS, controlled by the ``process_ocean_climatology`` config option.
+* The ``ocean_thermal`` test case has two steps: ``build_mapping_file`` and
+  ``process_thermal_forcing``. For AIS this produces 3D thermal forcing (with
+  30 ocean depth layers); for GrIS it produces 2D (depth-averaged) thermal
+  forcing. The processing step can also handle the observational ocean thermal
+  forcing climatology (Zhou et al.) for AIS, controlled by the
+  ``process_ocean_climatology`` config option.
 
-* The ``fracture`` test case has three steps: ``process_excess_melt``
-  (Path A), ``process_lake_properties`` (Path B), and
+* The ``fracture`` test case has four steps: ``build_mapping_file``,
+  ``process_excess_melt`` (Path A), ``process_lake_properties`` (Path B), and
   ``process_shelf_collapse`` (Path C). It processes the ISMIP7
   surface-melt-driven ice shelf collapse forcing (AIS only).
 
@@ -54,6 +57,58 @@ To use this test group, users need to:
    combination to process the surface-melt-driven ice shelf collapse
    pathways (excess melt, lake properties, and the ice shelf collapse mask).
 
+.. _landice_ismip7_forcing_workflow_optimization:
+
+Workflow Optimization
+~~~~~~~~~~~~~~~~~~~~~
+
+Each test case separates weight-generation (``build_mapping_file`` step) from
+processing (``process_*`` steps) to enable efficient resource allocation.
+``ESMF_RegridWeightGen`` benefits from many MPI tasks (128-512) but runs for
+only 5-10 minutes, while the processing steps run efficiently on a single node
+but may take hours to remap dozens of yearly files.
+
+**Separate allocation strategy**: Run ``build_mapping_file`` on a large
+allocation, then run the processing steps on a smaller allocation:
+
+.. code-block:: bash
+
+   # Allocate 128+ tasks for weight generation (5-10 minutes)
+   compass run -s build_mapping_file
+
+   # Allocate 1 task for processing (hours)
+   compass run -s process_smb process_temperature process_smb_gradient \
+               process_temperature_gradient process_runoff
+
+This avoids wasting hundreds of node-hours by holding a large allocation during
+the long processing phase.
+
+**Weight reuse across scenarios**: Mapping files depend only on ``ice_sheet``,
+``mali_mesh_name``, and ``method_remap``—not on model or scenario. This means
+weights built for ssp585 are identical to those for ssp126 (same mesh and
+method) and can be reused via the ``mapping_files_path`` config option:
+
+.. code-block:: cfg
+
+   [ismip7]
+   # Point to a previous run's mapping_files directory
+   mapping_files_path = /path/to/output_base_path/mapping_files/
+
+When ``mapping_files_path`` is set, ``build_mapping_file`` symlinks any existing
+weight files from that directory and builds only the missing ones. Built weights
+are automatically copied to ``<output_base_path>/mapping_files/`` for reuse in
+future runs.
+
+**Typical multi-scenario workflow**:
+
+1. Process the first scenario (e.g., ssp126) normally. Built weights are saved
+   to ``<output_base_path>/mapping_files/``.
+
+2. For subsequent scenarios with the same mesh and methods, set
+   ``mapping_files_path`` to reuse the weights. The ``build_mapping_file`` step
+   completes instantly (just symlinking), and you can skip the large allocation
+   entirely.
+
 Example user config files are provided in the source tree for local testing:
 
 * ``compass/landice/tests/ismip7_forcing/ismip7_forcing_test.cfg``
@@ -211,6 +266,13 @@ values are:
    # Number of MPI tasks for ESMF_RegridWeightGen
    esmf_ntasks = 128
 
+   # Optional path to a directory of pre-built mapping files for reuse across runs.
+   # If provided, the test case will symlink any existing, canonically-named weight
+   # files from this directory and build only the missing ones. To reuse weights from
+   # a previous run, point this at <prior_output_base_path>/mapping_files/.
+   # If not provided or set to NotAvailable, all weight files are built from scratch.
+   mapping_files_path = NotAvailable
+
    # Whether to process time-varying ocean thermal forcing (ESM scenario data)
    process_ocean_thermal = true
 
@@ -294,6 +356,13 @@ grid to the MALI unstructured mesh.
 
 Steps:
 
+* **build_mapping_file**: Builds the ESMF regridding weights from the ISMIP7
+  atmosphere grid to the MALI mesh. This step runs ``ESMF_RegridWeightGen``
+  with ``esmf_ntasks`` MPI tasks. One mapping file is built and shared across
+  all five atmosphere variables (they use the same source grid). Built weights
+  are copied to ``<output_base_path>/mapping_files/`` for reuse across
+  scenarios.
+
 * **process_smb**: Remaps the surface mass balance (``acabf``) field. The
   output variable is ``sfcMassBal``.
 
@@ -320,17 +389,27 @@ The ``landice/ismip7_forcing/ocean_thermal`` test case processes the ISMIP7
 ocean thermal forcing (``tf``) and remaps it from the native polar
 stereographic grid to the MALI unstructured mesh.
 
-The step supports two processing modes, controlled by boolean config options
-in the ``[ismip7]`` section:
+Steps:
+
+* **build_mapping_file**: Builds the ESMF regridding weights from the ISMIP7
+  ocean grid to the MALI mesh. This step runs ``ESMF_RegridWeightGen`` with
+  ``esmf_ntasks`` MPI tasks. One mapping file is built and shared across
+  scenario and climatology processing (if both are enabled and use the same
+  remapping method). Built weights are copied to
+  ``<output_base_path>/mapping_files/`` for reuse across scenarios.
+
+* **process_thermal_forcing**: Processes the ocean thermal forcing data. This
+  step supports two processing modes, controlled by boolean config options in
+  the ``[ismip7]`` section:
 
-* **Scenario (time-varying) data** (``process_ocean_thermal = true``):
-  Processes ESM-driven thermal forcing for a given model/scenario combination.
+  * **Scenario (time-varying) data** (``process_ocean_thermal = true``):
+    Processes ESM-driven thermal forcing for a given model/scenario combination.
 
-* **Observational climatology** (``process_ocean_climatology = true``):
-  Processes the static Zhou et al. observational thermal forcing climatology
-  (AIS only). This is a time-invariant 3D field referenced to 1995-2024.
+  * **Observational climatology** (``process_ocean_climatology = true``):
+    Processes the static Zhou et al. observational thermal forcing climatology
+    (AIS only). This is a time-invariant 3D field referenced to 1995-2024.
 
-Both modes can be enabled simultaneously.
+  Both modes can be enabled simultaneously.
 
 For **AIS** scenario data, thermal forcing is 3D with 30 vertical ocean
 layers. The input files span decades (e.g., 1850-1859). The output variable
@@ -353,8 +432,9 @@ fracture
 
 The ``landice/ismip7_forcing/fracture`` test case processes the ISMIP7
 surface-melt-driven ice shelf collapse forcing (AIS only). It implements the
-three ISMIP7 pathways as separate steps, each remapping annual fields from
-the native 8km polar stereographic grid onto the MALI unstructured mesh.
+three ISMIP7 pathways as separate processing steps, each remapping annual
+fields from the native 8km polar stereographic grid onto the MALI unstructured
+mesh.
 
 All three source files are discovered from the ``fracture/{version}/``
 subdirectory of ``base_path_ismip7``.
@@ -364,6 +444,16 @@ remapping-method config option to ``None`` in the ``[ismip7_fracture]``
 section (for example, ``method_remap_excess_melt = None`` skips Path A). This
 is useful when only some of the pathway source files are available.
 
+Steps:
+
+* **build_mapping_file**: Builds ESMF regridding weights from the ISMIP7
+  fracture grid to the MALI mesh. This step runs ``ESMF_RegridWeightGen`` with
+  ``esmf_ntasks`` MPI tasks. Up to three mapping files may be built (one per
+  enabled pathway), depending on whether the pathways use different remapping
+  methods. If all three pathways use the same method, one mapping file is built
+  and shared. Built weights are copied to ``<output_base_path>/mapping_files/``
+  for reuse across scenarios.
+
 * **process_excess_melt** (Path A): Remaps the excess meltwater field
   (melt + rain after firn air content depletion), matching
   ``excess_melt_*.nc``. The output variable is ``ismip7ExcessMelt``