diff --git a/lib/config/migrations/custom/match-managers-migration.spec.ts b/lib/config/migrations/custom/match-managers-migration.spec.ts
deleted file mode 100644
index 8c7d519520f0e4..00000000000000
--- a/lib/config/migrations/custom/match-managers-migration.spec.ts
+++ /dev/null
@@ -1,26 +0,0 @@
-import { MatchManagersMigration } from './match-managers-migration';
-
-describe('config/migrations/custom/match-managers-migration', () => {
-  it('migrates old custom manager syntax to new one', () => {
-    expect(MatchManagersMigration).toMigrate(
-      {
-        matchManagers: ['npm', 'regex', 'custom.someMgr'],
-      },
-      {
-        matchManagers: ['npm', 'custom.regex', 'custom.someMgr'],
-      }
-    );
-  });
-
-  // coverage
-  it('only migrates when necessary', () => {
-    expect(MatchManagersMigration).not.toMigrate(
-      {
-        matchManagers: undefined,
-      },
-      {
-        matchManagers: undefined,
-      }
-    );
-  });
-});
diff --git a/lib/config/migrations/custom/match-managers-migration.ts b/lib/config/migrations/custom/match-managers-migration.ts
deleted file mode 100644
index 81457fca2b891d..00000000000000
--- a/lib/config/migrations/custom/match-managers-migration.ts
+++ /dev/null
@@ -1,18 +0,0 @@
-import is from '@sindresorhus/is';
-import { isCustomManager } from '../../../modules/manager/custom';
-import { AbstractMigration } from '../base/abstract-migration';
-
-export class MatchManagersMigration extends AbstractMigration {
-  override readonly propertyName = 'matchManagers';
-
-  override run(value: unknown): void {
-    if (!is.array<string>(value, is.string)) {
-      return;
-    }
-
-    const newValue = value.map((manager) =>
-      isCustomManager(manager) ? `custom.${manager}` : manager
-    );
-    this.rewrite(newValue);
-  }
-}
diff --git a/lib/config/validation-helpers/managers.spec.ts b/lib/config/validation-helpers/managers.spec.ts
index 943d1e57f0e9c4..653f65bf2bf357 100644
--- a/lib/config/validation-helpers/managers.spec.ts
+++ b/lib/config/validation-helpers/managers.spec.ts
@@ -3,7 +3,7 @@ import { check } from './managers';
 describe('config/validation-helpers/managers', () => {
   it('should have no errors', () => {
     const res = check({
-      resolvedRule: { matchManagers: ['npm', 'regex', 'custom.regex'] },
+      resolvedRule: { matchManagers: ['npm', 'regex'] },
       currentPath: '',
     });
     expect(res).toEqual([]);
diff --git a/lib/config/validation-helpers/managers.ts b/lib/config/validation-helpers/managers.ts
index bf930ef2c8a979..aecad19df3c483 100644
--- a/lib/config/validation-helpers/managers.ts
+++ b/lib/config/validation-helpers/managers.ts
@@ -13,8 +13,7 @@ export function check({
   if (Array.isArray(resolvedRule.matchManagers)) {
     if (
       resolvedRule.matchManagers.find(
-        (confManager) =>
-          !allManagersList.includes(confManager.replace('custom.', ''))
+        (confManager) => !allManagersList.includes(confManager)
       )
     ) {
       managersErrMessage = `${currentPath}:
diff --git a/lib/util/package-rules/managers.spec.ts b/lib/util/package-rules/managers.spec.ts
index c5a00ab509b336..c8e855c87e7fd2 100644
--- a/lib/util/package-rules/managers.spec.ts
+++ b/lib/util/package-rules/managers.spec.ts
@@ -47,17 +47,5 @@ describe('util/package-rules/managers', () => {
       );
       expect(result).toBeFalse();
     });
-
-    it('should match custom managers', () => {
-      const result = managersMatcher.matches(
-        {
-          manager: 'regex',
-        },
-        {
-          matchManagers: ['custom.regex'],
-        }
-      );
-      expect(result).toBeTrue();
-    });
   });
 });
diff --git a/lib/util/package-rules/managers.ts b/lib/util/package-rules/managers.ts
index 6ceffdb9057987..cd5de99a2ad26e 100644
--- a/lib/util/package-rules/managers.ts
+++ b/lib/util/package-rules/managers.ts
@@ -1,6 +1,5 @@
 import is from '@sindresorhus/is';
 import type { PackageRule, PackageRuleInputConfig } from '../../config/types';
-import { isCustomManager } from '../../modules/manager/custom';
 import { Matcher } from './base';
 
 export class ManagersMatcher extends Matcher {
@@ -14,9 +13,6 @@ export class ManagersMatcher extends Matcher {
     if (is.undefined(manager) || !manager) {
       return false;
     }
-    if (isCustomManager(manager)) {
-      return matchManagers.includes(`custom.${manager}`);
-    }
     return matchManagers.includes(manager);
   }
 }