diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 113d92c..8bd3450 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -71,6 +71,8 @@
 import android.net.INetworkPolicyListener;
 import android.net.INetworkPolicyManager;
 import android.net.INetworkStatsService;
+import android.net.InetAddresses;
+import android.net.IpPrefix;
 import android.net.LinkProperties;
 import android.net.LinkProperties.CompareResult;
 import android.net.MatchAllNetworkSpecifier;
@@ -1740,6 +1742,12 @@
                 }
             }
         }
+
+        @Override
+        public void onNat64PrefixEvent(int netId, boolean added,
+                                       String prefixString, int prefixLength) {
+            mHandler.post(() -> handleNat64PrefixEvent(netId, added, prefixString, prefixLength));
+        }
     };
 
     @VisibleForTesting
@@ -2762,6 +2770,29 @@
         handleUpdateLinkProperties(nai, new LinkProperties(nai.linkProperties));
     }
 
+    private void handleNat64PrefixEvent(int netId, boolean added, String prefixString,
+            int prefixLength) {
+        NetworkAgentInfo nai = mNetworkForNetId.get(netId);
+        if (nai == null) return;
+
+        log(String.format("NAT64 prefix %s on netId %d: %s/%d",
+                          (added ? "added" : "removed"), netId, prefixString, prefixLength));
+
+        IpPrefix prefix = null;
+        if (added) {
+            try {
+                prefix = new IpPrefix(InetAddresses.parseNumericAddress(prefixString),
+                        prefixLength);
+            } catch (IllegalArgumentException e) {
+                loge("Invalid NAT64 prefix " + prefixString + "/" + prefixLength);
+                return;
+            }
+        }
+
+        nai.clatd.setNat64Prefix(prefix);
+        handleUpdateLinkProperties(nai, new LinkProperties(nai.linkProperties));
+    }
+
     private void updateLingerState(NetworkAgentInfo nai, long now) {
         // 1. Update the linger timer. If it's changed, reschedule or cancel the alarm.
         // 2. If the network was lingering and there are now requests, unlinger it.
diff --git a/services/core/java/com/android/server/connectivity/Nat464Xlat.java b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
index c834eaa..7b7fc0d 100644
--- a/services/core/java/com/android/server/connectivity/Nat464Xlat.java
+++ b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
@@ -18,7 +18,9 @@
 
 import android.net.ConnectivityManager;
 import android.net.INetd;
+import android.net.InetAddresses;
 import android.net.InterfaceConfiguration;
+import android.net.IpPrefix;
 import android.net.LinkAddress;
 import android.net.LinkProperties;
 import android.net.NetworkInfo;
@@ -31,6 +33,7 @@
 import com.android.server.net.BaseNetworkObserver;
 
 import java.net.Inet4Address;
+import java.net.Inet6Address;
 import java.util.Objects;
 
 /**
@@ -72,8 +75,10 @@
         RUNNING,    // start() called, and the stacked iface is known to be up.
     }
 
+    private IpPrefix mNat64Prefix;
     private String mBaseIface;
     private String mIface;
+    private Inet6Address mIPv6Address;
     private State mState = State.IDLE;
 
     public Nat464Xlat(NetworkAgentInfo nai, INetd netd, INetworkManagementService nmService) {
@@ -91,12 +96,17 @@
         // TODO: migrate to NetworkCapabilities.TRANSPORT_*.
         final boolean supported = ArrayUtils.contains(NETWORK_TYPES, nai.networkInfo.getType());
         final boolean connected = ArrayUtils.contains(NETWORK_STATES, nai.networkInfo.getState());
-        // We only run clat on networks that don't have a native IPv4 address.
-        final boolean hasIPv4Address =
-                (nai.linkProperties != null) && nai.linkProperties.hasIPv4Address();
-        final boolean skip464xlat =
-                (nai.netMisc() != null) && nai.netMisc().skip464xlat;
-        return supported && connected && !hasIPv4Address && !skip464xlat;
+
+        // We only run clat on networks that have a global IPv6 address and a NAT64 prefix and don't
+        // have a native IPv4 address.
+        LinkProperties lp = nai.linkProperties;
+        final boolean isNat64Network = (lp != null) && lp.hasGlobalIPv6Address()
+                && lp.getNat64Prefix() != null && !lp.hasIPv4Address();
+
+        // If the network tells us it doesn't use clat, respect that.
+        final boolean skip464xlat = (nai.netMisc() != null) && nai.netMisc().skip464xlat;
+
+        return supported && connected && isNat64Network && !skip464xlat;
     }
 
     /**
@@ -132,14 +142,21 @@
             Slog.e(TAG, "Can't register interface observer for clat on " + mNetwork.name());
             return;
         }
+
+        String addrStr = null;
         try {
-            mNetd.clatdStart(baseIface);
+            addrStr = mNetd.clatdStart(baseIface, mNat64Prefix.toString());
         } catch (RemoteException | IllegalStateException e) {
             Slog.e(TAG, "Error starting clatd on " + baseIface, e);
         }
         mIface = CLAT_PREFIX + baseIface;
         mBaseIface = baseIface;
         mState = State.STARTING;
+        try {
+            mIPv6Address = (Inet6Address) InetAddresses.parseNumericAddress(addrStr);
+        } catch (ClassCastException | IllegalArgumentException | NullPointerException e) {
+            Slog.e(TAG, "Invalid IPv6 address " + addrStr);
+        }
     }
 
     /**
@@ -220,12 +237,18 @@
         }
     }
 
+    public void setNat64Prefix(IpPrefix nat64Prefix) {
+        mNat64Prefix = nat64Prefix;
+    }
+
     /**
      * Copies the stacked clat link in oldLp, if any, to the passed LinkProperties.
      * This is necessary because the LinkProperties in mNetwork come from the transport layer, which
      * has no idea that 464xlat is running on top of it.
      */
     public void fixupLinkProperties(LinkProperties oldLp, LinkProperties lp) {
+        lp.setNat64Prefix(mNat64Prefix);
+
         if (!isRunning()) {
             return;
         }
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index 8ec8e78..18008b6 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -1798,6 +1798,12 @@
                     fn.test((NetworkCapabilities) cbi.arg));
         }
 
+        void expectLinkPropertiesLike(Predicate<LinkProperties> fn, MockNetworkAgent agent) {
+            CallbackInfo cbi = expectCallback(CallbackState.LINK_PROPERTIES, agent);
+            assertTrue("Received LinkProperties don't match expectations : " + cbi.arg,
+                    fn.test((LinkProperties) cbi.arg));
+        }
+
         void expectBlockedStatusCallback(boolean expectBlocked, MockNetworkAgent agent) {
             CallbackInfo cbi = expectCallback(CallbackState.BLOCKED_STATUS, agent);
             boolean actualBlocked = (boolean) cbi.arg;
@@ -5087,6 +5093,9 @@
     public void testStackedLinkProperties() throws UnknownHostException, RemoteException {
         final LinkAddress myIpv4 = new LinkAddress("1.2.3.4/24");
         final LinkAddress myIpv6 = new LinkAddress("2001:db8:1::1/64");
+        final String kNat64PrefixString = "2001:db8:64:64:64:64::";
+        final IpPrefix kNat64Prefix = new IpPrefix(InetAddress.getByName(kNat64PrefixString), 96);
+
         final NetworkRequest networkRequest = new NetworkRequest.Builder()
                 .addTransportType(TRANSPORT_CELLULAR)
                 .addCapability(NET_CAPABILITY_INTERNET)
@@ -5110,10 +5119,19 @@
         mCellNetworkAgent.sendLinkProperties(cellLp);
         mCellNetworkAgent.connect(true);
         networkCallback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
-        verify(mMockNetd, times(1)).clatdStart(MOBILE_IFNAME);
-        Nat464Xlat clat = mService.getNat464Xlat(mCellNetworkAgent);
 
-        // Clat iface up, expect stack link updated.
+        // When NAT64 prefix detection succeeds, LinkProperties are updated and clatd is started.
+        Nat464Xlat clat = mService.getNat464Xlat(mCellNetworkAgent);
+        assertNull(mCm.getLinkProperties(mCellNetworkAgent.getNetwork()).getNat64Prefix());
+        mService.mNetdEventCallback.onNat64PrefixEvent(mCellNetworkAgent.getNetwork().netId,
+                true /* added */, kNat64PrefixString, 96);
+        LinkProperties lpBeforeClat = (LinkProperties) networkCallback.expectCallback(
+                CallbackState.LINK_PROPERTIES, mCellNetworkAgent).arg;
+        assertEquals(0, lpBeforeClat.getStackedLinks().size());
+        assertEquals(kNat64Prefix, lpBeforeClat.getNat64Prefix());
+        verify(mMockNetd, times(1)).clatdStart(MOBILE_IFNAME, kNat64Prefix.toString());
+
+        // Clat iface comes up. Expect stacked link to be added.
         clat.interfaceLinkStateChanged(CLAT_PREFIX + MOBILE_IFNAME, true);
         networkCallback.expectCallback(CallbackState.LINK_PROPERTIES, mCellNetworkAgent);
         List<LinkProperties> stackedLps = mCm.getLinkProperties(mCellNetworkAgent.getNetwork())
@@ -5130,20 +5148,50 @@
         assertNotEquals(stackedLpsAfterChange, Collections.EMPTY_LIST);
         assertEquals(makeClatLinkProperties(myIpv4), stackedLpsAfterChange.get(0));
 
-        // Add ipv4 address, expect stacked linkproperties be cleaned up
+        // Add ipv4 address, expect that clatd is stopped and stacked linkproperties are cleaned up.
         cellLp.addLinkAddress(myIpv4);
         cellLp.addRoute(new RouteInfo(myIpv4, null, MOBILE_IFNAME));
         mCellNetworkAgent.sendLinkProperties(cellLp);
         networkCallback.expectCallback(CallbackState.LINK_PROPERTIES, mCellNetworkAgent);
         verify(mMockNetd, times(1)).clatdStop(MOBILE_IFNAME);
-
-        // Clat iface removed, expect linkproperties revert to original one
-        clat.interfaceRemoved(CLAT_PREFIX + MOBILE_IFNAME);
         networkCallback.expectCallback(CallbackState.LINK_PROPERTIES, mCellNetworkAgent);
-        LinkProperties actualLpAfterIpv4 = mCm.getLinkProperties(mCellNetworkAgent.getNetwork());
-        assertEquals(cellLp, actualLpAfterIpv4);
 
-        // Clean up
+        // As soon as stop is called, the linkproperties lose the stacked interface.
+        LinkProperties actualLpAfterIpv4 = mCm.getLinkProperties(mCellNetworkAgent.getNetwork());
+        LinkProperties expected = new LinkProperties(cellLp);
+        expected.setNat64Prefix(kNat64Prefix);
+        assertEquals(expected, actualLpAfterIpv4);
+        assertEquals(0, actualLpAfterIpv4.getStackedLinks().size());
+
+        // The interface removed callback happens but has no effect after stop is called.
+        clat.interfaceRemoved(CLAT_PREFIX + MOBILE_IFNAME);
+        networkCallback.assertNoCallback();
+
+        reset(mMockNetd);
+
+        // Remove IPv4 address and expect clatd to be started again.
+        cellLp.removeLinkAddress(myIpv4);
+        cellLp.removeRoute(new RouteInfo(myIpv4, null, MOBILE_IFNAME));
+        cellLp.removeDnsServer(InetAddress.getByName("8.8.8.8"));
+        mCellNetworkAgent.sendLinkProperties(cellLp);
+        networkCallback.expectCallback(CallbackState.LINK_PROPERTIES, mCellNetworkAgent);
+        verify(mMockNetd, times(1)).clatdStart(MOBILE_IFNAME, kNat64Prefix.toString());
+
+        // Clat iface comes up. Expect stacked link to be added.
+        clat.interfaceLinkStateChanged(CLAT_PREFIX + MOBILE_IFNAME, true);
+        networkCallback.expectLinkPropertiesLike((lp) -> lp.getStackedLinks().size() == 1,
+                mCellNetworkAgent);
+
+        // NAT64 prefix is removed. Expect that clat is stopped.
+        mService.mNetdEventCallback.onNat64PrefixEvent(mCellNetworkAgent.getNetwork().netId,
+                false /* added */, kNat64PrefixString, 96);
+        networkCallback.expectLinkPropertiesLike((lp) -> lp.getNat64Prefix() == null,
+                mCellNetworkAgent);
+        verify(mMockNetd, times(1)).clatdStop(MOBILE_IFNAME);
+        networkCallback.expectLinkPropertiesLike((lp) -> lp.getStackedLinks().size() == 0,
+                mCellNetworkAgent);
+
+        // Clean up.
         mCellNetworkAgent.disconnect();
         networkCallback.expectCallback(CallbackState.LOST, mCellNetworkAgent);
         networkCallback.assertNoCallback();
diff --git a/tests/net/java/com/android/server/connectivity/Nat464XlatTest.java b/tests/net/java/com/android/server/connectivity/Nat464XlatTest.java
index b9450b3..9b7ff31 100644
--- a/tests/net/java/com/android/server/connectivity/Nat464XlatTest.java
+++ b/tests/net/java/com/android/server/connectivity/Nat464XlatTest.java
@@ -16,6 +16,7 @@
 
 package com.android.server.connectivity;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.eq;
@@ -28,6 +29,7 @@
 import android.net.ConnectivityManager;
 import android.net.INetd;
 import android.net.InterfaceConfiguration;
+import android.net.IpPrefix;
 import android.net.LinkAddress;
 import android.net.LinkProperties;
 import android.net.NetworkInfo;
@@ -55,6 +57,7 @@
     static final String BASE_IFACE = "test0";
     static final String STACKED_IFACE = "v4-test0";
     static final LinkAddress ADDR = new LinkAddress("192.0.2.5/29");
+    static final String NAT64_PREFIX = "64:ff9b::/96";
 
     @Mock ConnectivityService mConnectivity;
     @Mock NetworkMisc mMisc;
@@ -89,6 +92,15 @@
         when(mConfig.getLinkAddress()).thenReturn(ADDR);
     }
 
+    private void assertRequiresClat(boolean expected, NetworkAgentInfo nai) {
+        String msg = String.format("requiresClat expected %b for type=%d state=%s skip464xlat=%b "
+                + "nat64Prefix=%s addresses=%s", expected, nai.networkInfo.getType(),
+                nai.networkInfo.getDetailedState(),
+                mMisc.skip464xlat, nai.linkProperties.getNat64Prefix(),
+                nai.linkProperties.getLinkAddresses());
+        assertEquals(msg, expected, Nat464Xlat.requiresClat(nai));
+    }
+
     @Test
     public void testRequiresClat() throws Exception {
         final int[] supportedTypes = {
@@ -104,20 +116,31 @@
             NetworkInfo.DetailedState.SUSPENDED,
         };
 
+        LinkProperties oldLp = new LinkProperties(mNai.linkProperties);
         for (int type : supportedTypes) {
             mNai.networkInfo.setType(type);
             for (NetworkInfo.DetailedState state : supportedDetailedStates) {
                 mNai.networkInfo.setDetailedState(state, "reason", "extraInfo");
-                String msg = String.format("requiresClat expected for type=%d state=%s",
-                        type, state);
+
+                mNai.linkProperties.setNat64Prefix(new IpPrefix("2001:db8:0:64::/96"));
+                assertRequiresClat(false, mNai);
+
+                mNai.linkProperties.addLinkAddress(new LinkAddress("fc00::1/64"));
+                assertRequiresClat(false, mNai);
+
+                mNai.linkProperties.addLinkAddress(new LinkAddress("2001:db8::1/64"));
+                assertRequiresClat(true, mNai);
 
                 mMisc.skip464xlat = true;
-                String errorMsg = msg + String.format(" skip464xlat=%b", mMisc.skip464xlat);
-                assertFalse(errorMsg, Nat464Xlat.requiresClat(mNai));
+                assertRequiresClat(false, mNai);
 
                 mMisc.skip464xlat = false;
-                errorMsg = msg + String.format(" skip464xlat=%b", mMisc.skip464xlat);
-                assertTrue(errorMsg, Nat464Xlat.requiresClat(mNai));
+                assertRequiresClat(true, mNai);
+
+                mNai.linkProperties.addLinkAddress(new LinkAddress("192.0.2.2/24"));
+                assertRequiresClat(false, mNai);
+
+                mNai.linkProperties = new LinkProperties(oldLp);
             }
         }
     }
@@ -127,11 +150,13 @@
         Nat464Xlat nat = makeNat464Xlat();
         ArgumentCaptor<LinkProperties> c = ArgumentCaptor.forClass(LinkProperties.class);
 
+        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+
         // ConnectivityService starts clat.
         nat.start();
 
         verify(mNms).registerObserver(eq(nat));
-        verify(mNetd).clatdStart(eq(BASE_IFACE));
+        verify(mNetd).clatdStart(eq(BASE_IFACE), eq(NAT64_PREFIX));
 
         // Stacked interface up notification arrives.
         nat.interfaceLinkStateChanged(STACKED_IFACE, true);
@@ -165,10 +190,12 @@
         ArgumentCaptor<LinkProperties> c = ArgumentCaptor.forClass(LinkProperties.class);
         InOrder inOrder = inOrder(mNetd, mConnectivity);
 
+        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+
         // ConnectivityService starts clat.
         nat.start();
 
-        inOrder.verify(mNetd).clatdStart(eq(BASE_IFACE));
+        inOrder.verify(mNetd).clatdStart(eq(BASE_IFACE), eq(NAT64_PREFIX));
 
         // Stacked interface up notification arrives.
         nat.interfaceLinkStateChanged(STACKED_IFACE, true);
@@ -205,7 +232,7 @@
         // ConnectivityService starts clatd again.
         nat.start();
 
-        inOrder.verify(mNetd).clatdStart(eq(BASE_IFACE));
+        inOrder.verify(mNetd).clatdStart(eq(BASE_IFACE), eq(NAT64_PREFIX));
 
         if (!interfaceRemovedFirst) {
             // Stacked interface removed notification arrives and is ignored.
@@ -252,11 +279,13 @@
         Nat464Xlat nat = makeNat464Xlat();
         ArgumentCaptor<LinkProperties> c = ArgumentCaptor.forClass(LinkProperties.class);
 
+        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+
         // ConnectivityService starts clat.
         nat.start();
 
         verify(mNms).registerObserver(eq(nat));
-        verify(mNetd).clatdStart(eq(BASE_IFACE));
+        verify(mNetd).clatdStart(eq(BASE_IFACE), eq(NAT64_PREFIX));
 
         // Stacked interface up notification arrives.
         nat.interfaceLinkStateChanged(STACKED_IFACE, true);
@@ -289,11 +318,13 @@
     public void testStopBeforeClatdStarts() throws Exception {
         Nat464Xlat nat = makeNat464Xlat();
 
+        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+
         // ConnectivityService starts clat.
         nat.start();
 
         verify(mNms).registerObserver(eq(nat));
-        verify(mNetd).clatdStart(eq(BASE_IFACE));
+        verify(mNetd).clatdStart(eq(BASE_IFACE), eq(NAT64_PREFIX));
 
         // ConnectivityService immediately stops clat (Network disconnects, IPv4 addr appears, ...)
         nat.stop();
@@ -320,11 +351,13 @@
     public void testStopAndClatdNeverStarts() throws Exception {
         Nat464Xlat nat = makeNat464Xlat();
 
+        nat.setNat64Prefix(new IpPrefix(NAT64_PREFIX));
+
         // ConnectivityService starts clat.
         nat.start();
 
         verify(mNms).registerObserver(eq(nat));
-        verify(mNetd).clatdStart(eq(BASE_IFACE));
+        verify(mNetd).clatdStart(eq(BASE_IFACE), eq(NAT64_PREFIX));
 
         // ConnectivityService immediately stops clat (Network disconnects, IPv4 addr appears, ...)
         nat.stop();