diff --git a/packages/playwright/src/reporters/json.ts b/packages/playwright/src/reporters/json.ts
index 1a20225812..f0bb1ecbb7 100644
--- a/packages/playwright/src/reporters/json.ts
+++ b/packages/playwright/src/reporters/json.ts
@@ -55,10 +55,10 @@ class JSONReporter extends EmptyReporter {
   }
 
   override async onEnd(result: FullResult) {
-    await outputReport(this._serializeReport(), this.config, this._outputFile);
+    await outputReport(this._serializeReport(result), this.config, this._outputFile);
   }
 
-  private _serializeReport(): JSONReport {
+  private _serializeReport(result: FullResult): JSONReport {
     return {
       config: {
         ...removePrivateFields(this.config),
@@ -79,7 +79,11 @@ class JSONReporter extends EmptyReporter {
         })
       },
       suites: this._mergeSuites(this.suite.suites),
-      errors: this._errors
+      errors: this._errors,
+      stats: {
+        startTime: result.startTime.toISOString(),
+        duration: result.duration,
+      },
     };
   }
 
@@ -194,7 +198,7 @@ class JSONReporter extends EmptyReporter {
       stderr: result.stderr.map(s => stdioEntry(s)),
       retry: result.retry,
       steps: steps.length ? steps.map(s => this._serializeTestStep(s)) : undefined,
-      startTime: result.startTime,
+      startTime: result.startTime.toISOString(),
       attachments: result.attachments.map(a => ({
         name: a.name,
         contentType: a.contentType,
diff --git a/packages/playwright/types/testReporter.d.ts b/packages/playwright/types/testReporter.d.ts
index 42211ef9b5..0b3a472e08 100644
--- a/packages/playwright/types/testReporter.d.ts
+++ b/packages/playwright/types/testReporter.d.ts
@@ -504,6 +504,10 @@ export interface JSONReport {
   };
   suites: JSONReportSuite[];
   errors: TestError[];
+  stats: {
+    startTime: string; // Date in ISO 8601 format.
+    duration: number; // In milliseconds;
+  }
 }
 
 export interface JSONReportSuite {
@@ -551,7 +555,7 @@ export interface JSONReportTestResult {
   stderr: JSONReportSTDIOEntry[];
   retry: number;
   steps?: JSONReportTestStep[];
-  startTime: Date;
+  startTime: string; // Date in ISO 8601 format.
   attachments: {
     name: string;
     path?: string;
diff --git a/tests/playwright-test/reporter-json.spec.ts b/tests/playwright-test/reporter-json.spec.ts
index b8775cf669..2148c2cfe0 100644
--- a/tests/playwright-test/reporter-json.spec.ts
+++ b/tests/playwright-test/reporter-json.spec.ts
@@ -63,7 +63,7 @@ test('should not report skipped due to sharding', async ({ runInlineTest }) => {
   expect(result.report.suites[0].specs[1].tests[0].status).toBe('skipped');
 });
 
-test('should report projects', async ({ runInlineTest }, testInfo) => {
+test('should report projects and stats', async ({ runInlineTest }, testInfo) => {
   const result = await runInlineTest({
     'playwright.config.ts': `
       module.exports = {
@@ -107,6 +107,9 @@ test('should report projects', async ({ runInlineTest }, testInfo) => {
 
   expect(result.report.suites[0].specs[0].tests[0].projectName).toBe('p1');
   expect(result.report.suites[0].specs[0].tests[1].projectName).toBe('p2');
+
+  expect(new Date(result.report.stats.startTime).valueOf()).not.toBeNaN();
+  expect(result.report.stats.duration).toEqual(expect.any(Number));
 });
 
 test('should show steps', async ({ runInlineTest }) => {
diff --git a/utils/generate_types/overrides-testReporter.d.ts b/utils/generate_types/overrides-testReporter.d.ts
index 61a20f42fa..fe371001af 100644
--- a/utils/generate_types/overrides-testReporter.d.ts
+++ b/utils/generate_types/overrides-testReporter.d.ts
@@ -75,6 +75,10 @@ export interface JSONReport {
   };
   suites: JSONReportSuite[];
   errors: TestError[];
+  stats: {
+    startTime: string; // Date in ISO 8601 format.
+    duration: number; // In milliseconds;
+  }
 }
 
 export interface JSONReportSuite {
@@ -122,7 +126,7 @@ export interface JSONReportTestResult {
   stderr: JSONReportSTDIOEntry[];
   retry: number;
   steps?: JSONReportTestStep[];
-  startTime: Date;
+  startTime: string; // Date in ISO 8601 format.
   attachments: {
     name: string;
     path?: string;