diff --git a/packages/playwright-core/src/protocol/validator.ts b/packages/playwright-core/src/protocol/validator.ts
index a7aad29c90..b4fef0d2c1 100644
--- a/packages/playwright-core/src/protocol/validator.ts
+++ b/packages/playwright-core/src/protocol/validator.ts
@@ -590,6 +590,10 @@ scheme.BrowserCloseParams = tOptional(tObject({}));
 scheme.BrowserCloseResult = tOptional(tObject({}));
 scheme.BrowserKillForTestsParams = tOptional(tObject({}));
 scheme.BrowserKillForTestsResult = tOptional(tObject({}));
+scheme.BrowserDefaultUserAgentForTestParams = tOptional(tObject({}));
+scheme.BrowserDefaultUserAgentForTestResult = tObject({
+  userAgent: tString,
+});
 scheme.BrowserNewContextParams = tObject({
   noDefaultViewport: tOptional(tBoolean),
   viewport: tOptional(tObject({
diff --git a/packages/playwright-core/src/server/dispatchers/browserDispatcher.ts b/packages/playwright-core/src/server/dispatchers/browserDispatcher.ts
index 43fdab9e48..3d3dcd8213 100644
--- a/packages/playwright-core/src/server/dispatchers/browserDispatcher.ts
+++ b/packages/playwright-core/src/server/dispatchers/browserDispatcher.ts
@@ -59,6 +59,10 @@ export class BrowserDispatcher extends Dispatcher<Browser, channels.BrowserChann
     await this._object.killForTests();
   }
 
+  async defaultUserAgentForTest(): Promise<channels.BrowserDefaultUserAgentForTestResult> {
+    return { userAgent: this._object.userAgent() };
+  }
+
   async newBrowserCDPSession(): Promise<channels.BrowserNewBrowserCDPSessionResult> {
     if (!this._object.options.isChromium)
       throw new Error(`CDP session is only available in Chromium`);
@@ -116,6 +120,10 @@ export class ConnectedBrowserDispatcher extends Dispatcher<Browser, channels.Bro
     // Client should not send us Browser.killForTests.
   }
 
+  async defaultUserAgentForTest(): Promise<channels.BrowserDefaultUserAgentForTestResult> {
+    throw new Error('Client should not send us Browser.defaultUserAgentForTest');
+  }
+
   async newBrowserCDPSession(): Promise<channels.BrowserNewBrowserCDPSessionResult> {
     if (!this._object.options.isChromium)
       throw new Error(`CDP session is only available in Chromium`);
diff --git a/packages/playwright-core/src/server/webkit/wkBrowser.ts b/packages/playwright-core/src/server/webkit/wkBrowser.ts
index d62752aece..84ff6ac30f 100644
--- a/packages/playwright-core/src/server/webkit/wkBrowser.ts
+++ b/packages/playwright-core/src/server/webkit/wkBrowser.ts
@@ -50,6 +50,7 @@ export class WKBrowser extends Browser {
       browser._browserSession.send('Playwright.enable'),
     ];
     if (options.persistent) {
+      options.persistent.userAgent ||= DEFAULT_USER_AGENT;
       browser._defaultContext = new WKBrowserContext(browser, undefined, options.persistent);
       promises.push((browser._defaultContext as WKBrowserContext)._initialize());
     }
diff --git a/packages/protocol/src/channels.ts b/packages/protocol/src/channels.ts
index 32c287d289..7e968288b7 100644
--- a/packages/protocol/src/channels.ts
+++ b/packages/protocol/src/channels.ts
@@ -1083,6 +1083,7 @@ export interface BrowserChannel extends BrowserEventTarget, Channel {
   _type_Browser: boolean;
   close(params?: BrowserCloseParams, metadata?: CallMetadata): Promise<BrowserCloseResult>;
   killForTests(params?: BrowserKillForTestsParams, metadata?: CallMetadata): Promise<BrowserKillForTestsResult>;
+  defaultUserAgentForTest(params?: BrowserDefaultUserAgentForTestParams, metadata?: CallMetadata): Promise<BrowserDefaultUserAgentForTestResult>;
   newContext(params: BrowserNewContextParams, metadata?: CallMetadata): Promise<BrowserNewContextResult>;
   newContextForReuse(params: BrowserNewContextForReuseParams, metadata?: CallMetadata): Promise<BrowserNewContextForReuseResult>;
   newBrowserCDPSession(params?: BrowserNewBrowserCDPSessionParams, metadata?: CallMetadata): Promise<BrowserNewBrowserCDPSessionResult>;
@@ -1096,6 +1097,11 @@ export type BrowserCloseResult = void;
 export type BrowserKillForTestsParams = {};
 export type BrowserKillForTestsOptions = {};
 export type BrowserKillForTestsResult = void;
+export type BrowserDefaultUserAgentForTestParams = {};
+export type BrowserDefaultUserAgentForTestOptions = {};
+export type BrowserDefaultUserAgentForTestResult = {
+  userAgent: string,
+};
 export type BrowserNewContextParams = {
   noDefaultViewport?: boolean,
   viewport?: {
diff --git a/packages/protocol/src/protocol.yml b/packages/protocol/src/protocol.yml
index 005b67458b..1ced5dbf89 100644
--- a/packages/protocol/src/protocol.yml
+++ b/packages/protocol/src/protocol.yml
@@ -897,6 +897,10 @@ Browser:
 
     killForTests:
 
+    defaultUserAgentForTest:
+      returns:
+        userAgent: string
+
     newContext:
       parameters:
         $mixin: ContextOptions
diff --git a/tests/library/browsercontext-basic.spec.ts b/tests/library/browsercontext-basic.spec.ts
index 53a1afbf86..07f026123e 100644
--- a/tests/library/browsercontext-basic.spec.ts
+++ b/tests/library/browsercontext-basic.spec.ts
@@ -288,3 +288,8 @@ it('should emulate media in cross-process iframe', async ({ browser, server }) =
   expect(await frame.evaluate(() => matchMedia('(prefers-color-scheme: dark)').matches)).toBe(true);
   await page.close();
 });
+
+it('default user agent', async ({ launchPersistent, browser, page }) => {
+  const { userAgent } = await (browser as any)._channel.defaultUserAgentForTest();
+  expect(await page.evaluate(() => navigator.userAgent)).toBe(userAgent);
+});
diff --git a/tests/library/defaultbrowsercontext-2.spec.ts b/tests/library/defaultbrowsercontext-2.spec.ts
index 4babd8e278..99d46d1f43 100644
--- a/tests/library/defaultbrowsercontext-2.spec.ts
+++ b/tests/library/defaultbrowsercontext-2.spec.ts
@@ -233,3 +233,9 @@ it('should support har option', async ({ launchPersistent, asset }) => {
   await expect(page.locator('body')).toHaveCSS('background-color', 'rgb(255, 0, 0)');
 });
 
+it('user agent is up to date', async ({ launchPersistent, browser }) => {
+  const { userAgent } = await (browser as any)._channel.defaultUserAgentForTest();
+  const { context, page } = await launchPersistent();
+  expect(await page.evaluate(() => navigator.userAgent)).toBe(userAgent);
+  await context.close();
+});