diff --git a/webdev/lib/src/command/configuration.dart b/webdev/lib/src/command/configuration.dart
index 51598870e..59cd2cfc5 100644
--- a/webdev/lib/src/command/configuration.dart
+++ b/webdev/lib/src/command/configuration.dart
@@ -37,6 +37,7 @@ const nullSafetyAuto = 'auto';
 const disableDdsFlag = 'disable-dds';
 const enableExperimentOption = 'enable-experiment';
 const canaryFeaturesFlag = 'canary';
+const offlineFlag = 'offline';
 
 ReloadConfiguration _parseReloadConfiguration(ArgResults argResults) {
   var auto = argResults.options.contains(autoOption)
@@ -107,6 +108,7 @@ class Configuration {
   final String? _nullSafety;
   final List<String>? _experiments;
   final bool? _canaryFeatures;
+  final bool? _offline;
 
   Configuration({
     bool? autoRun,
@@ -133,6 +135,7 @@ class Configuration {
     String? nullSafety,
     List<String>? experiments,
     bool? canaryFeatures,
+    bool? offline,
   })  : _autoRun = autoRun,
         _chromeDebugPort = chromeDebugPort,
         _debugExtension = debugExtension,
@@ -154,7 +157,8 @@ class Configuration {
         _verbose = verbose,
         _nullSafety = nullSafety,
         _experiments = experiments,
-        _canaryFeatures = canaryFeatures {
+        _canaryFeatures = canaryFeatures,
+        _offline = offline {
     _validateConfiguration();
   }
 
@@ -229,7 +233,8 @@ class Configuration {
       verbose: other._verbose ?? _verbose,
       nullSafety: other._nullSafety ?? _nullSafety,
       experiments: other._experiments ?? _experiments,
-      canaryFeatures: other._canaryFeatures ?? _canaryFeatures);
+      canaryFeatures: other._canaryFeatures ?? _canaryFeatures,
+      offline: other._offline ?? _offline);
 
   factory Configuration.noInjectedClientDefaults() =>
       Configuration(autoRun: false, debug: false, debugExtension: false);
@@ -284,6 +289,8 @@ class Configuration {
 
   bool get canaryFeatures => _canaryFeatures ?? false;
 
+  bool get offline => _offline ?? false;
+
   /// Returns a new configuration with values updated from the parsed args.
   static Configuration fromArgs(ArgResults? argResults,
       {Configuration? defaultConfiguration}) {
@@ -408,6 +415,10 @@ class Configuration {
         ? argResults[canaryFeaturesFlag] as bool?
         : defaultConfiguration.canaryFeatures;
 
+    var offline = argResults.options.contains(offlineFlag)
+        ? argResults[offlineFlag] as bool?
+        : defaultConfiguration.verbose;
+
     return Configuration(
       autoRun: defaultConfiguration.autoRun,
       chromeDebugPort: chromeDebugPort,
@@ -433,6 +444,7 @@ class Configuration {
       nullSafety: nullSafety,
       experiments: experiments,
       canaryFeatures: canaryFeatures,
+      offline: offline,
     );
   }
 }
diff --git a/webdev/lib/src/command/shared.dart b/webdev/lib/src/command/shared.dart
index e05c31da8..0eeb9ee4e 100644
--- a/webdev/lib/src/command/shared.dart
+++ b/webdev/lib/src/command/shared.dart
@@ -74,7 +74,11 @@ void addSharedArgs(ArgParser argParser,
         abbr: 'v',
         defaultsTo: false,
         negatable: false,
-        help: 'Enables verbose logging.');
+        help: 'Enables verbose logging.')
+    ..addFlag(offlineFlag,
+        defaultsTo: false,
+        negatable: false,
+        help: 'Disable feching from pub.dev.');
 }
 
 /// Parses the provided [Configuration] to return a list of
@@ -103,7 +107,9 @@ List<String> buildRunnerArgs(Configuration configuration) {
 }
 
 Future<void> validatePubspecLock(Configuration configuration) async {
-  final pubspecLock = await PubspecLock.read();
+  final pubspecLock = await PubspecLock.read(
+    offline: configuration.offline
+  );
   await checkPubspecLock(pubspecLock,
       requireBuildWebCompilers: configuration.requireBuildWebCompilers);
 }
diff --git a/webdev/lib/src/pubspec.dart b/webdev/lib/src/pubspec.dart
index 6bcec17b3..d3d79d106 100644
--- a/webdev/lib/src/pubspec.dart
+++ b/webdev/lib/src/pubspec.dart
@@ -68,8 +68,12 @@ class PubspecLock {
 
   PubspecLock(this._packages);
 
-  static Future<PubspecLock> read() async {
-    await _runPubDeps();
+  static Future<PubspecLock> read({
+    bool offline = false
+  }) async {
+    if (!offline) {
+      await _runPubDeps();
+    }
     var dir = p.absolute(p.current);
     while (true) {
       final candidate = p.join(
diff --git a/webdev/test/installation_test.dart b/webdev/test/installation_test.dart
index d79674521..6ac972c4f 100644
--- a/webdev/test/installation_test.dart
+++ b/webdev/test/installation_test.dart
@@ -30,6 +30,14 @@ void main() {
   Process? serveProcess;
   Directory? tempDir0;
 
+  final testScript =
+      File(p.join(p.dirname(Platform.script.toFilePath()), 'test.dart'))
+          .readAsStringSync();
+  final thisScript = File.fromUri(Uri.parse(testScript.substring(
+      testScript.lastIndexOf('import', testScript.indexOf('as test;')) + 8,
+      testScript.indexOf('as test;') - 2)));
+  final packageDir = p.dirname(p.dirname(thisScript.path));
+
   Future<void> expectStdoutAndCleanExit(Process process,
       {required String expectedStdout}) async {
     final stdoutCompleter = _captureOutput(
@@ -127,7 +135,7 @@ void main() {
     // Verify that `dart pub global activate` works:
     activateProcess = await Process.start(
       'dart',
-      ['pub', 'global', 'activate', 'webdev'],
+      ['pub', 'global', 'activate', '--source', 'path', packageDir],
     );
     await expectStdoutAndCleanExit(
       activateProcess!,
@@ -141,6 +149,41 @@ void main() {
     await expectStdoutThenExit(serveProcess!,
         expectedStdout: 'Serving `web` on');
   });
+
+  test('activate and serve webdev fails with offline', () async {
+    final tempDir = tempDir0!;
+    final tempPath = tempDir.path;
+
+    // Verify that we can create a new Dart app:
+    createProcess = await Process.start(
+      'dart',
+      ['create', '--no-pub', '--template', 'web', 'temp_app'],
+      workingDirectory: tempPath,
+    );
+    await expectStdoutAndCleanExit(
+      createProcess!,
+      expectedStdout: 'Created project temp_app in temp_app!',
+    );
+    final appPath = p.join(tempPath, 'temp_app');
+    expect(await Directory(appPath).exists(), isTrue);
+
+    // Verify that `dart pub global activate` works:
+    activateProcess = await Process.start(
+      'dart',
+      ['pub', 'global', 'activate', '--source', 'path', packageDir],
+    );
+    await expectStdoutAndCleanExit(
+      activateProcess!,
+      expectedStdout: 'Activated webdev',
+    );
+
+    // Verify that `webdev serve` works for our new app:
+    serveProcess = await Process.start('dart',
+        ['pub', 'global', 'run', 'webdev', 'serve', '--offline', 'web:8081'],
+        workingDirectory: appPath);
+    await expectStdoutThenExit(serveProcess!,
+        expectedStdout: 'Cannot open file\n  pubspec.lock\n');
+  });
 }
 
 Future<int> _waitForExitOrTimeout(Process process) {