diff --git a/packages/flutter_tools/lib/src/android/android_device.dart b/packages/flutter_tools/lib/src/android/android_device.dart
index bf9515d3cf..85035a9342 100644
--- a/packages/flutter_tools/lib/src/android/android_device.dart
+++ b/packages/flutter_tools/lib/src/android/android_device.dart
@@ -17,6 +17,7 @@ import '../build_configuration.dart';
 import '../device.dart';
 import '../flx.dart' as flx;
 import '../globals.dart';
+import '../service_protocol.dart';
 import '../toolchain.dart';
 import 'adb.dart';
 import 'android.dart';
@@ -185,12 +186,12 @@ class AndroidDevice extends Device {
     return true;
   }
 
-  Future<Null> _forwardObservatoryPort(int port) async {
-    bool portWasZero = port == 0;
+  Future<Null> _forwardObservatoryPort(int devicePort, int port) async {
+    bool portWasZero = (port == null) || (port == 0);
 
     try {
       // Set up port forwarding for observatory.
-      port = await portForwarder.forward(observatoryDefaultPort,
+      port = await portForwarder.forward(devicePort,
                                          hostPort: port);
       if (portWasZero)
         printStatus('Observatory listening on http://127.0.0.1:$port');
@@ -214,13 +215,18 @@ class AndroidDevice extends Device {
       return false;
     }
 
-    await _forwardObservatoryPort(debugPort);
-
     if (clearLogs)
       this.clearLogs();
 
     runCheckedSync(adbCommandForDevice(<String>['push', bundlePath, _deviceBundlePath]));
 
+    ServiceProtocolDiscovery serviceProtocolDiscovery =
+        new ServiceProtocolDiscovery(logReader);
+
+    // We take this future here but do not wait for completion until *after*
+    // we start the bundle.
+    Future<int> serviceProtocolPort = serviceProtocolDiscovery.nextPort();
+
     List<String> cmd = adbCommandForDevice(<String>[
       'shell', 'am', 'start',
       '-a', 'android.intent.action.RUN',
@@ -243,6 +249,13 @@ class AndroidDevice extends Device {
       printError(result.trim());
       return false;
     }
+
+    // Wait for the service protocol port here. This will complete once
+    // the device has printed "Observatory is listening on..."
+    int devicePort = await serviceProtocolPort;
+    printTrace('service protocol port = $devicePort');
+    await _forwardObservatoryPort(devicePort, debugPort);
+
     return true;
   }
 
diff --git a/packages/flutter_tools/lib/src/ios/devices.dart b/packages/flutter_tools/lib/src/ios/devices.dart
index c7f84d3b06..c618a5fbe9 100644
--- a/packages/flutter_tools/lib/src/ios/devices.dart
+++ b/packages/flutter_tools/lib/src/ios/devices.dart
@@ -199,7 +199,6 @@ class IOSDevice extends Device {
       return false;
     }
 
-    printTrace('Installation successful.');
     return true;
   }
 
diff --git a/packages/flutter_tools/lib/src/ios/simulators.dart b/packages/flutter_tools/lib/src/ios/simulators.dart
index fe02d31f8f..567cdcd078 100644
--- a/packages/flutter_tools/lib/src/ios/simulators.dart
+++ b/packages/flutter_tools/lib/src/ios/simulators.dart
@@ -16,6 +16,7 @@ import '../build_configuration.dart';
 import '../device.dart';
 import '../flx.dart' as flx;
 import '../globals.dart';
+import '../service_protocol.dart';
 import '../toolchain.dart';
 import 'mac.dart';
 
@@ -462,6 +463,13 @@ class IOSSimulator extends Device {
     if (!(await _setupUpdatedApplicationBundle(app, toolchain)))
       return false;
 
+    ServiceProtocolDiscovery serviceProtocolDiscovery =
+        new ServiceProtocolDiscovery(logReader);
+
+    // We take this future here but do not wait for completion until *after*
+    // we start the application.
+    Future<int> serviceProtocolPort = serviceProtocolDiscovery.nextPort();
+
     // Prepare launch arguments.
     List<String> args = <String>[
       "--flx=${path.absolute(path.join('build', 'app.flx'))}",
@@ -486,7 +494,12 @@ class IOSSimulator extends Device {
       return false;
     }
 
+    // Wait for the service protocol port here. This will complete once
+    // the device has printed "Observatory is listening on..."
+    int devicePort = await serviceProtocolPort;
+    printTrace('service protocol port = $devicePort');
     printTrace('Successfully started ${app.name} on $id.');
+    printStatus('Observatory listening on http://127.0.0.1:$devicePort');
 
     return true;
   }
diff --git a/packages/flutter_tools/lib/src/service_protocol.dart b/packages/flutter_tools/lib/src/service_protocol.dart
index db3bbbed20..70b6183204 100644
--- a/packages/flutter_tools/lib/src/service_protocol.dart
+++ b/packages/flutter_tools/lib/src/service_protocol.dart
@@ -29,7 +29,7 @@ class ServiceProtocolDiscovery {
 
   void _onLine(String line) {
     int portNumber = 0;
-    if (line.startsWith('Observatory listening on http://')) {
+    if (line.contains('Observatory listening on http://')) {
       try {
         RegExp portExp = new RegExp(r"\d+.\d+.\d+.\d+:(\d+)");
         String port = portExp.firstMatch(line).group(1);
diff --git a/packages/flutter_tools/test/service_protocol_test.dart b/packages/flutter_tools/test/service_protocol_test.dart
index 5f5d5c6bdf..621266be0a 100644
--- a/packages/flutter_tools/test/service_protocol_test.dart
+++ b/packages/flutter_tools/test/service_protocol_test.dart
@@ -40,6 +40,11 @@ void main() {
       const Duration(milliseconds: 100), onTimeout: () => 77);
       // Expect the timeout port.
       expect(port, 77);
+      // Get next port future.
+      nextPort = discoverer.nextPort();
+      logReader.addLine(
+          'I/flutter : Observatory listening on http://127.0.0.1:52584');
+      expect(await nextPort, 52584);
     });
   });
 }