diff --git a/dwds/debug_extension_mv3/web/background.dart b/dwds/debug_extension_mv3/web/background.dart
index 1ccec7d2e..97cd2df94 100644
--- a/dwds/debug_extension_mv3/web/background.dart
+++ b/dwds/debug_extension_mv3/web/background.dart
@@ -17,6 +17,10 @@ import 'messaging.dart';
 import 'storage.dart';
 import 'utils.dart';
 
+// Note: The extension tests wait for this string to be logged to the console to
+// ensure that the Dart app has been detected:
+const dartAppDetectedMsg = 'Dart app detected.';
+
 void main() {
   _registerListeners();
 }
@@ -210,6 +214,9 @@ Future<void> _updateIcon(int activeTabId) async {
     tabId: activeTabId,
   );
   multipleApps == null ? _setDebuggableIcon() : _setWarningIcon();
+  // Do not remove. This is required by the tests to wait for detection of the
+  // Dart app:
+  debugLog(dartAppDetectedMsg);
 }
 
 void _setDebuggableIcon() {
diff --git a/dwds/test/puppeteer/extension_common.dart b/dwds/test/puppeteer/extension_common.dart
index e9f34ce2a..0800d77fe 100644
--- a/dwds/test/puppeteer/extension_common.dart
+++ b/dwds/test/puppeteer/extension_common.dart
@@ -177,6 +177,7 @@ void testAll({
             backgroundPage: backgroundPage,
           );
           // Click on the Dart Debug Extension icon:
+          await _waitForDartDetection(hasServiceWorker: isMV3);
           await workerEvalDelay(secondsToWait: 2);
           await clickOnExtensionIcon(
             worker: worker,
@@ -290,7 +291,7 @@ void testAll({
           final appTab =
               await navigateToPage(browser, url: appUrl, isNew: true);
           // Click on the Dart Debug Extension icon:
-          await workerEvalDelay(secondsToWait: 2);
+          await _waitForDartDetection(hasServiceWorker: isMV3);
           await clickOnExtensionIcon(
             worker: worker,
             backgroundPage: backgroundPage,
@@ -320,7 +321,7 @@ void testAll({
           final appTab =
               await navigateToPage(browser, url: appUrl, isNew: true);
           // Click on the Dart Debug Extension icon:
-          await workerEvalDelay(secondsToWait: 2);
+          await _waitForDartDetection(hasServiceWorker: isMV3);
           await clickOnExtensionIcon(
             worker: worker,
             backgroundPage: backgroundPage,
@@ -347,7 +348,7 @@ void testAll({
           final appTab =
               await navigateToPage(browser, url: appUrl, isNew: true);
           // Click on the Dart Debug Extension icon:
-          await workerEvalDelay(secondsToWait: 2);
+          await _waitForDartDetection(hasServiceWorker: isMV3);
           print('[debug log] click on extension icon');
           await clickOnExtensionIcon(
             worker: worker,
@@ -423,7 +424,7 @@ void testAll({
           final appTab =
               await navigateToPage(browser, url: appUrl, isNew: true);
           // Click on the Dart Debug Extension icon:
-          await workerEvalDelay(secondsToWait: 2);
+          await _waitForDartDetection(hasServiceWorker: isMV3);
           await clickOnExtensionIcon(
             worker: worker,
             backgroundPage: backgroundPage,
@@ -963,6 +964,14 @@ void testAll({
   });
 }
 
+Future<bool> _waitForDartDetection({
+  required bool hasServiceWorker,
+}) {
+  final source =
+      hasServiceWorker ? ConsoleSource.worker : ConsoleSource.background;
+  return waitForConsoleLog('Dart app detected.', source: source);
+}
+
 Future<bool> _clickLaunchButton(
   Browser browser, {
   required Panel panel,
diff --git a/dwds/test/puppeteer/test_utils.dart b/dwds/test/puppeteer/test_utils.dart
index dcf7df31d..3b7bcbd5c 100644
--- a/dwds/test/puppeteer/test_utils.dart
+++ b/dwds/test/puppeteer/test_utils.dart
@@ -17,9 +17,9 @@ enum ConsoleSource {
   worker,
 }
 
-final _backgroundLogs = [];
-final _devToolsLogs = [];
-final _workerLogs = [];
+final _backgroundLogs = <String>[];
+final _devToolsLogs = <String>[];
+final _workerLogs = <String>[];
 
 Future<String> buildDebugExtension({required bool isMV3}) async {
   final extensionDir = absolutePath(pathFromDwds: 'debug_extension_mv3');
@@ -198,6 +198,41 @@ String getExtensionOrigin(Browser browser) {
   return '$chromeExtension//$extensionId';
 }
 
+Future<bool> waitForConsoleLog(
+  String textToMatch, {
+  required ConsoleSource source,
+  Duration timeBetween = const Duration(milliseconds: 500),
+  int retries = 10,
+}) async {
+  await Future.delayed(timeBetween);
+  List<String> logs;
+  switch (source) {
+    case ConsoleSource.background:
+      logs = _backgroundLogs;
+      break;
+    case ConsoleSource.devTools:
+      logs = _devToolsLogs;
+      break;
+    case ConsoleSource.worker:
+      logs = _workerLogs;
+      break;
+  }
+  final foundText = logs.where((log) => log.contains(textToMatch)).isNotEmpty;
+  if (foundText) {
+    return true;
+  }
+  if (retries > 0) {
+    final retriesLeft = retries - 1;
+    return waitForConsoleLog(
+      textToMatch,
+      source: source,
+      timeBetween: timeBetween,
+      retries: retriesLeft,
+    );
+  }
+  return false;
+}
+
 void _saveConsoleMsg({
   required ConsoleSource source,
   required String type,