diff --git a/goldens/public-api/angular/build/index.api.md b/goldens/public-api/angular/build/index.api.md
index 2615db9fd0b0..0e6a3375d8fb 100644
--- a/goldens/public-api/angular/build/index.api.md
+++ b/goldens/public-api/angular/build/index.api.md
@@ -235,7 +235,7 @@ export type UnitTestBuilderOptions = {
     progress?: boolean;
     providersFile?: string;
     reporters?: SchemaReporter[];
-    runner: Runner;
+    runner?: Runner;
     setupFiles?: string[];
     tsConfig?: string;
     watch?: boolean;
diff --git a/packages/angular/build/src/builders/unit-test/options.ts b/packages/angular/build/src/builders/unit-test/options.ts
index c94acc27a932..33792ce89e8f 100644
--- a/packages/angular/build/src/builders/unit-test/options.ts
+++ b/packages/angular/build/src/builders/unit-test/options.ts
@@ -82,7 +82,7 @@ export async function normalizeOptions(
     include: options.include ?? ['**/*.spec.ts'],
     exclude: options.exclude,
     filter,
-    runnerName: runner,
+    runnerName: runner ?? 'vitest',
     coverage: options.coverage
       ? {
           all: options.coverageAll,
diff --git a/packages/angular/build/src/builders/unit-test/schema.json b/packages/angular/build/src/builders/unit-test/schema.json
index 668cc8639a09..1cce0bf34e53 100644
--- a/packages/angular/build/src/builders/unit-test/schema.json
+++ b/packages/angular/build/src/builders/unit-test/schema.json
@@ -16,6 +16,7 @@
     "runner": {
       "type": "string",
       "description": "Specifies the test runner to use for test execution.",
+      "default": "vitest",
       "enum": ["karma", "vitest"]
     },
     "browsers": {
@@ -267,5 +268,5 @@
     }
   },
   "additionalProperties": false,
-  "required": ["runner"]
+  "required": []
 }
diff --git a/tests/legacy-cli/e2e/utils/vitest.ts b/tests/legacy-cli/e2e/utils/vitest.ts
index 95929703cf9b..ca856243592a 100644
--- a/tests/legacy-cli/e2e/utils/vitest.ts
+++ b/tests/legacy-cli/e2e/utils/vitest.ts
@@ -19,11 +19,7 @@ export async function applyVitestBuilder(): Promise<void> {
     // Update to Vitest builder.
     const test = project['architect']['test'];
     test['builder'] = '@angular/build:unit-test';
-    test['options'] = {
-      tsConfig: test['options']['tsConfig'],
-      buildTarget: '::development',
-      runner: 'vitest',
-    };
+    test['options'] = {};
   });
 
   await updateJsonFile('tsconfig.spec.json', (tsconfig) => {