diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 2f2e79a..b0cc38c 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -3356,6 +3356,22 @@
     }
 
     /**
+     * Requests that the system open the captive portal app on the specified network.
+     *
+     * @param network The network to log into.
+     *
+     * @hide
+     */
+    @RequiresPermission(android.Manifest.permission.CONNECTIVITY_INTERNAL)
+    public void startCaptivePortalApp(Network network) {
+        try {
+            mService.startCaptivePortalApp(network);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
      * It is acceptable to briefly use multipath data to provide seamless connectivity for
      * time-sensitive user-facing operations when the system default network is temporarily
      * unresponsive. The amount of data should be limited (less than one megabyte for every call to
diff --git a/core/java/android/net/IConnectivityManager.aidl b/core/java/android/net/IConnectivityManager.aidl
index 425e494..6b2da61 100644
--- a/core/java/android/net/IConnectivityManager.aidl
+++ b/core/java/android/net/IConnectivityManager.aidl
@@ -160,6 +160,7 @@
 
     void setAcceptUnvalidated(in Network network, boolean accept, boolean always);
     void setAvoidUnvalidated(in Network network);
+    void startCaptivePortalApp(in Network network);
 
     int getMultipathPreference(in Network Network);
 
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index d5adf48..7ae4138 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -2636,6 +2636,17 @@
                 PROMPT_UNVALIDATED_DELAY_MS);
     }
 
+    @Override
+    public void startCaptivePortalApp(Network network) {
+        enforceConnectivityInternalPermission();
+        mHandler.post(() -> {
+            NetworkAgentInfo nai = getNetworkAgentInfoForNetwork(network);
+            if (nai == null) return;
+            if (!nai.networkCapabilities.hasCapability(NET_CAPABILITY_CAPTIVE_PORTAL)) return;
+            nai.networkMonitor.sendMessage(NetworkMonitor.CMD_LAUNCH_CAPTIVE_PORTAL_APP);
+        });
+    }
+
     public boolean avoidBadWifi() {
         return mMultinetworkPolicyTracker.getAvoidBadWifi();
     }
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index 6140a89..6e5ac8a 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -39,6 +39,7 @@
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.res.Resources;
+import android.net.CaptivePortal;
 import android.net.ConnectivityManager;
 import android.net.ConnectivityManager.NetworkCallback;
 import android.net.ConnectivityManager.PacketKeepalive;
@@ -77,6 +78,7 @@
 import android.os.Parcelable;
 import android.os.Process;
 import android.os.SystemClock;
+import android.os.UserHandle;
 import android.provider.Settings;
 import android.test.AndroidTestCase;
 import android.test.mock.MockContentResolver;
@@ -121,7 +123,7 @@
     private static final int TIMEOUT_MS = 500;
     private static final int TEST_LINGER_DELAY_MS = 120;
 
-    private BroadcastInterceptingContext mServiceContext;
+    private MockContext mServiceContext;
     private WrappedConnectivityService mService;
     private WrappedConnectivityManager mCm;
     private MockNetworkAgent mWiFiNetworkAgent;
@@ -152,6 +154,7 @@
         private final MockContentResolver mContentResolver;
 
         @Spy private Resources mResources;
+        private final LinkedBlockingQueue<Intent> mStartedActivities = new LinkedBlockingQueue<>();
 
         MockContext(Context base) {
             super(base);
@@ -169,6 +172,27 @@
         }
 
         @Override
+        public void startActivityAsUser(Intent intent, UserHandle handle) {
+            mStartedActivities.offer(intent);
+        }
+
+        public Intent expectStartActivityIntent(int timeoutMs) {
+            Intent intent = null;
+            try {
+                intent = mStartedActivities.poll(timeoutMs, TimeUnit.MILLISECONDS);
+            } catch (InterruptedException e) {}
+            assertNotNull("Did not receive sign-in intent after " + timeoutMs + "ms", intent);
+            return intent;
+        }
+
+        public void expectNoStartActivityIntent(int timeoutMs) {
+            try {
+                assertNull("Received unexpected Intent to start activity",
+                        mStartedActivities.poll(timeoutMs, TimeUnit.MILLISECONDS));
+            } catch (InterruptedException e) {}
+        }
+
+        @Override
         public Object getSystemService(String name) {
             if (Context.CONNECTIVITY_SERVICE.equals(name)) return mCm;
             if (Context.NOTIFICATION_SERVICE.equals(name)) return mock(NotificationManager.class);
@@ -1830,6 +1854,52 @@
     }
 
     @SmallTest
+    public void testCaptivePortalApp() {
+        final TestNetworkCallback captivePortalCallback = new TestNetworkCallback();
+        final NetworkRequest captivePortalRequest = new NetworkRequest.Builder()
+                .addCapability(NET_CAPABILITY_CAPTIVE_PORTAL).build();
+        mCm.registerNetworkCallback(captivePortalRequest, captivePortalCallback);
+
+        final TestNetworkCallback validatedCallback = new TestNetworkCallback();
+        final NetworkRequest validatedRequest = new NetworkRequest.Builder()
+                .addCapability(NET_CAPABILITY_VALIDATED).build();
+        mCm.registerNetworkCallback(validatedRequest, validatedCallback);
+
+        // Bring up wifi.
+        mWiFiNetworkAgent = new MockNetworkAgent(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.connect(true);
+        validatedCallback.expectAvailableAndValidatedCallbacks(mWiFiNetworkAgent);
+        Network wifiNetwork = mWiFiNetworkAgent.getNetwork();
+
+        // Check that calling startCaptivePortalApp does nothing.
+        final int fastTimeoutMs = 100;
+        mCm.startCaptivePortalApp(wifiNetwork);
+        mServiceContext.expectNoStartActivityIntent(fastTimeoutMs);
+
+        // Turn into a captive portal.
+        mWiFiNetworkAgent.getWrappedNetworkMonitor().gen204ProbeResult = 302;
+        mCm.reportNetworkConnectivity(wifiNetwork, false);
+        captivePortalCallback.expectAvailableCallbacks(mWiFiNetworkAgent);
+        validatedCallback.expectCallback(CallbackState.LOST, mWiFiNetworkAgent);
+
+        // Check that startCaptivePortalApp sends the expected intent.
+        mCm.startCaptivePortalApp(wifiNetwork);
+        Intent intent = mServiceContext.expectStartActivityIntent(TIMEOUT_MS);
+        assertEquals(ConnectivityManager.ACTION_CAPTIVE_PORTAL_SIGN_IN, intent.getAction());
+        assertEquals(wifiNetwork, intent.getExtra(ConnectivityManager.EXTRA_NETWORK));
+
+        // Have the app report that the captive portal is dismissed, and check that we revalidate.
+        mWiFiNetworkAgent.getWrappedNetworkMonitor().gen204ProbeResult = 204;
+        CaptivePortal c = (CaptivePortal) intent.getExtra(ConnectivityManager.EXTRA_CAPTIVE_PORTAL);
+        c.reportCaptivePortalDismissed();
+        validatedCallback.expectAvailableCallbacks(mWiFiNetworkAgent);
+        captivePortalCallback.expectCallback(CallbackState.LOST, mWiFiNetworkAgent);
+
+        mCm.unregisterNetworkCallback(validatedCallback);
+        mCm.unregisterNetworkCallback(captivePortalCallback);
+    }
+
+    @SmallTest
     public void testAvoidOrIgnoreCaptivePortals() {
         final TestNetworkCallback captivePortalCallback = new TestNetworkCallback();
         final NetworkRequest captivePortalRequest = new NetworkRequest.Builder()