diff --git a/packages/shorebird_cli/lib/src/commands/preview_command.dart b/packages/shorebird_cli/lib/src/commands/preview_command.dart
index 220b22af..f4cfd689 100644
--- a/packages/shorebird_cli/lib/src/commands/preview_command.dart
+++ b/packages/shorebird_cli/lib/src/commands/preview_command.dart
@@ -247,6 +247,7 @@ class PreviewCommand extends ShorebirdCommand {
 
     final startAppProgress = logger.progress('Starting app');
     try {
+      await adb.clearAppData(package: package, deviceId: deviceId);
       await adb.startApp(package: package, deviceId: deviceId);
       startAppProgress.complete();
     } catch (error) {
diff --git a/packages/shorebird_cli/lib/src/executables/adb.dart b/packages/shorebird_cli/lib/src/executables/adb.dart
index c02db702..3024b90c 100644
--- a/packages/shorebird_cli/lib/src/executables/adb.dart
+++ b/packages/shorebird_cli/lib/src/executables/adb.dart
@@ -27,6 +27,21 @@ class Adb {
     return process.start(adbPath, command.split(' '));
   }
 
+  /// Clears the app data for the given [package] name.
+  Future<void> clearAppData({required String package, String? deviceId}) async {
+    final args = [
+      if (deviceId != null) ...['-s', deviceId],
+      'shell',
+      'pm',
+      'clear',
+      package,
+    ];
+    final result = await _exec(args.join(' '));
+    if (result.exitCode != 0) {
+      throw Exception('Unable to clear app data: ${result.stderr}');
+    }
+  }
+
   /// Starts the app with the given [package] name.
   Future<void> startApp({
     required String package,
diff --git a/packages/shorebird_cli/lib/src/executables/ios_deploy.dart b/packages/shorebird_cli/lib/src/executables/ios_deploy.dart
index f071beab..26590a86 100644
--- a/packages/shorebird_cli/lib/src/executables/ios_deploy.dart
+++ b/packages/shorebird_cli/lib/src/executables/ios_deploy.dart
@@ -160,6 +160,7 @@ Or run on an iOS simulator without code signing
         [
           '--debug',
           if (deviceId != null) ...['--id', deviceId],
+          '-r', // uninstall the app before reinstalling and clear app data
           '--bundle',
           bundlePath,
         ],
diff --git a/packages/shorebird_cli/test/src/commands/preview_command_test.dart b/packages/shorebird_cli/test/src/commands/preview_command_test.dart
index 9f0b0dfe..5bebb29c 100644
--- a/packages/shorebird_cli/test/src/commands/preview_command_test.dart
+++ b/packages/shorebird_cli/test/src/commands/preview_command_test.dart
@@ -247,6 +247,12 @@ void main() {
             deviceId: any(named: 'deviceId'),
           ),
         ).thenAnswer((_) async {});
+        when(
+          () => adb.clearAppData(
+            package: any(named: 'package'),
+            deviceId: any(named: 'deviceId'),
+          ),
+        ).thenAnswer((_) async {});
         when(
           () => adb.startApp(
             package: any(named: 'package'),
@@ -367,6 +373,23 @@ void main() {
         verify(() => bundletool.installApks(apks: apksPath())).called(1);
       });
 
+      test('exits with code 70 when clearing app data fails', () async {
+        when(
+          () => artifactManager.extractZip(
+            zipFile: any(named: 'zipFile'),
+            outputDirectory: any(named: 'outputDirectory'),
+          ),
+        ).thenAnswer(createShorebirdYaml);
+
+        final exception = Exception('oops');
+        when(
+          () => adb.clearAppData(package: any(named: 'package')),
+        ).thenThrow(exception);
+        final result = await runWithOverrides(command.run);
+        expect(result, equals(ExitCode.software.code));
+        verify(() => adb.clearAppData(package: packageName)).called(1);
+      });
+
       test('exits with code 70 when starting app fails', () async {
         when(
           () => artifactManager.extractZip(
diff --git a/packages/shorebird_cli/test/src/executables/adb_test.dart b/packages/shorebird_cli/test/src/executables/adb_test.dart
index c36663e1..5128086f 100644
--- a/packages/shorebird_cli/test/src/executables/adb_test.dart
+++ b/packages/shorebird_cli/test/src/executables/adb_test.dart
@@ -48,6 +48,71 @@ void main() {
       );
     });
 
+    group('clearAppData', () {
+      const package = 'com.example.app';
+      test('throws when unable to locate adb', () async {
+        when(() => androidSdk.adbPath).thenReturn(null);
+        await expectLater(
+          () => runWithOverrides(() => adb.clearAppData(package: package)),
+          throwsA(
+            isA<Exception>().having(
+              (e) => e.toString(),
+              'exception()',
+              contains('Unable to locate adb'),
+            ),
+          ),
+        );
+      });
+
+      test('throws process exits with non-zero exit code', () async {
+        when(
+          () => process.run(any(), any()),
+        ).thenAnswer(
+          (_) async => const ShorebirdProcessResult(
+            exitCode: 1,
+            stdout: '',
+            stderr: 'oops',
+          ),
+        );
+        await expectLater(
+          () => runWithOverrides(() => adb.clearAppData(package: package)),
+          throwsA(
+            isA<Exception>().having(
+              (e) => e.toString(),
+              'exception()',
+              contains('Unable to clear app data: oops'),
+            ),
+          ),
+        );
+      });
+
+      test('completes when process exits with 0', () async {
+        await expectLater(
+          runWithOverrides(() => adb.clearAppData(package: package)),
+          completes,
+        );
+        verify(
+          () => process.run(adbPath, 'shell pm clear $package'.split(' ')),
+        ).called(1);
+      });
+
+      test('forwards deviceId when provided', () async {
+        const deviceId = '1234';
+        await expectLater(
+          runWithOverrides(
+            () => adb.clearAppData(package: package, deviceId: deviceId),
+          ),
+          completes,
+        );
+        verify(
+          () => process.run(
+            adbPath,
+            '-s $deviceId shell pm clear $package'.split(' '),
+          ),
+        ).called(1);
+      });
+    });
+
     group('startApp', () {
       const package = 'com.example.app';
       test('throws when unable to locate adb', () async {
diff --git a/packages/shorebird_cli/test/src/executables/ios_deploy_test.dart b/packages/shorebird_cli/test/src/executables/ios_deploy_test.dart
index cdaa3d88..f04764a8 100644
--- a/packages/shorebird_cli/test/src/executables/ios_deploy_test.dart
+++ b/packages/shorebird_cli/test/src/executables/ios_deploy_test.dart
@@ -93,6 +93,7 @@ void main() {
             '--debug',
             '--id',
             deviceId,
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -113,6 +114,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -132,6 +134,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -157,6 +160,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -183,6 +187,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -207,6 +212,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -232,6 +238,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -257,6 +264,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -287,6 +295,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -312,6 +321,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),
@@ -336,6 +346,7 @@ void main() {
         verify(
           () => shorebirdProcess.start(any(that: endsWith('ios-deploy')), [
             '--debug',
+            '-r',
             '--bundle',
             bundlePath,
           ]),