diff --git a/src/lib/isLocale.js b/src/lib/isLocale.js
index ec84c8fce..72566bb38 100644
--- a/src/lib/isLocale.js
+++ b/src/lib/isLocale.js
@@ -30,7 +30,7 @@ const region = '([A-Za-z]{2}|\\d{3})';
   = 5*8alphanum         ; registered variants
   / (DIGIT 3alphanum)
  */
-const variant = '([A-Za-z0-9]{5,8}|(\\d[A-Z-a-z0-9]{3}))';
+const variant = '([A-Za-z0-9]{5,8}|(\\d[A-Za-z0-9]{3}))';
 
 /*
   = DIGIT               ; 0 - 9
diff --git a/test/validators.test.js b/test/validators.test.js
index 98d2a12ff..a53747c85 100644
--- a/test/validators.test.js
+++ b/test/validators.test.js
@@ -5714,6 +5714,14 @@ describe('Validators', () => {
     });
   });
 
+  it('should reject hyphens within digit-leading locale variants', () => {
+    test({
+      validator: 'isLocale',
+      valid: ['de-CH-1901', 'sl-rozaj-biske-1994', 'de_CH_1901'],
+      invalid: ['de-CH-190-', 'en-1--a', 'en-1-a-', 'en-1---'],
+    });
+  });
+
   it('should validate strings by byte length (deprecated api)', () => {
     test({
       validator: 'isByteLength',