diff --git a/service/src/com/android/server/connectivity/ClatCoordinator.java b/service/src/com/android/server/connectivity/ClatCoordinator.java
index e1c7b64..d7c3287 100644
--- a/service/src/com/android/server/connectivity/ClatCoordinator.java
+++ b/service/src/com/android/server/connectivity/ClatCoordinator.java
@@ -595,13 +595,17 @@
         Log.i(TAG, "untag socket cookie " + cookie);
     }
 
+    private boolean isStarted() {
+        return mClatdTracker != null;
+    }
+
     /**
      * Start clatd for a given interface and NAT64 prefix.
      */
     public String clatStart(final String iface, final int netId,
             @NonNull final IpPrefix nat64Prefix)
             throws IOException {
-        if (mClatdTracker != null) {
+        if (isStarted()) {
             throw new IOException("Clatd is already running on " + mClatdTracker.iface
                     + " (pid " + mClatdTracker.pid + ")");
         }
@@ -833,7 +837,7 @@
      * Stop clatd
      */
     public void clatStop() throws IOException {
-        if (mClatdTracker == null) {
+        if (!isStarted()) {
             throw new IOException("Clatd has not started");
         }
         Log.i(TAG, "Stopping clatd pid=" + mClatdTracker.pid + " on " + mClatdTracker.iface);
@@ -902,12 +906,16 @@
     public void dump(@NonNull IndentingPrintWriter pw) {
         // TODO: move map dump to a global place to avoid duplicate dump while there are two or
         // more IPv6 only networks.
-        pw.println("CLAT tracker: " + mClatdTracker.toString());
-        pw.println("Forwarding rules:");
-        pw.increaseIndent();
-        dumpBpfIngress(pw);
-        dumpBpfEgress(pw);
-        pw.decreaseIndent();
+        if (isStarted()) {
+            pw.println("CLAT tracker: " + mClatdTracker.toString());
+            pw.println("Forwarding rules:");
+            pw.increaseIndent();
+            dumpBpfIngress(pw);
+            dumpBpfEgress(pw);
+            pw.decreaseIndent();
+        } else {
+            pw.println("<not started>");
+        }
         pw.println();
     }
 
diff --git a/service/src/com/android/server/connectivity/Nat464Xlat.java b/service/src/com/android/server/connectivity/Nat464Xlat.java
index a57e992..4e19781 100644
--- a/service/src/com/android/server/connectivity/Nat464Xlat.java
+++ b/service/src/com/android/server/connectivity/Nat464Xlat.java
@@ -540,6 +540,9 @@
      */
     public void dump(IndentingPrintWriter pw) {
         if (SdkLevel.isAtLeastT()) {
+            // Dump ClatCoordinator information while clatd has been started but not running. The
+            // reason is that it helps to have more information if clatd is started but the
+            // v4-* interface doesn't bring up. See #isStarted, #isRunning.
             if (isStarted()) {
                 pw.println("ClatCoordinator:");
                 pw.increaseIndent();
diff --git a/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java b/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java
index 7646c19..85bc4a9 100644
--- a/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java
+++ b/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java
@@ -516,28 +516,38 @@
         assertEquals(65508, ClatCoordinator.adjustMtu(CLAT_MAX_MTU + 1 /* over maximum mtu */));
     }
 
-    @Test
-    public void testDump() throws Exception {
-        final ClatCoordinator coordinator = makeClatCoordinator();
+    private void verifyDump(final ClatCoordinator coordinator, boolean clatStarted) {
         final StringWriter stringWriter = new StringWriter();
         final IndentingPrintWriter ipw = new IndentingPrintWriter(stringWriter, " ");
-        coordinator.clatStart(BASE_IFACE, NETID, NAT64_IP_PREFIX);
         coordinator.dump(ipw);
 
         final String[] dumpStrings = stringWriter.toString().split("\n");
-        assertEquals(6, dumpStrings.length);
-        assertEquals("CLAT tracker: iface: test0 (1000), v4iface: v4-test0 (1001), "
-                + "v4: /192.0.0.46, v6: /2001:db8:0:b11::464, pfx96: /64:ff9b::, "
-                + "pid: 10483, cookie: 27149", dumpStrings[0].trim());
-        assertEquals("Forwarding rules:", dumpStrings[1].trim());
-        assertEquals("BPF ingress map: iif nat64Prefix v6Addr -> v4Addr oif",
-                dumpStrings[2].trim());
-        assertEquals("1000 /64:ff9b::/96 /2001:db8:0:b11::464 -> /192.0.0.46 1001",
-                dumpStrings[3].trim());
-        assertEquals("BPF egress map: iif v4Addr -> v6Addr nat64Prefix oif",
-                dumpStrings[4].trim());
-        assertEquals("1001 /192.0.0.46 -> /2001:db8:0:b11::464 /64:ff9b::/96 1000 ether",
-                dumpStrings[5].trim());
+        if (clatStarted) {
+            assertEquals(6, dumpStrings.length);
+            assertEquals("CLAT tracker: iface: test0 (1000), v4iface: v4-test0 (1001), "
+                    + "v4: /192.0.0.46, v6: /2001:db8:0:b11::464, pfx96: /64:ff9b::, "
+                    + "pid: 10483, cookie: 27149", dumpStrings[0].trim());
+            assertEquals("Forwarding rules:", dumpStrings[1].trim());
+            assertEquals("BPF ingress map: iif nat64Prefix v6Addr -> v4Addr oif",
+                    dumpStrings[2].trim());
+            assertEquals("1000 /64:ff9b::/96 /2001:db8:0:b11::464 -> /192.0.0.46 1001",
+                    dumpStrings[3].trim());
+            assertEquals("BPF egress map: iif v4Addr -> v6Addr nat64Prefix oif",
+                    dumpStrings[4].trim());
+            assertEquals("1001 /192.0.0.46 -> /2001:db8:0:b11::464 /64:ff9b::/96 1000 ether",
+                    dumpStrings[5].trim());
+        } else {
+            assertEquals(1, dumpStrings.length);
+            assertEquals("<not started>", dumpStrings[0].trim());
+        }
+    }
+
+    @Test
+    public void testDump() throws Exception {
+        final ClatCoordinator coordinator = makeClatCoordinator();
+        verifyDump(coordinator, false /* clatStarted */);
+        coordinator.clatStart(BASE_IFACE, NETID, NAT64_IP_PREFIX);
+        verifyDump(coordinator, true /* clatStarted */);
     }
 
     @Test
@@ -548,25 +558,18 @@
                 () -> coordinator.clatStart(BASE_IFACE, NETID, invalidPrefix));
     }
 
-    private void assertStartClat(final TestDependencies deps) throws Exception {
-        final ClatCoordinator coordinator = new ClatCoordinator(deps);
-        assertNotNull(coordinator.clatStart(BASE_IFACE, NETID, NAT64_IP_PREFIX));
-    }
-
-    private void assertNotStartClat(final TestDependencies deps) {
-        // Expect that the injection function of TestDependencies causes clatStart() failed.
-        final ClatCoordinator coordinator = new ClatCoordinator(deps);
-        assertThrows(IOException.class,
-                () -> coordinator.clatStart(BASE_IFACE, NETID, NAT64_IP_PREFIX));
-    }
-
     private void checkNotStartClat(final TestDependencies deps, final boolean needToCloseTunFd,
             final boolean needToClosePacketSockFd, final boolean needToCloseRawSockFd)
             throws Exception {
-        // [1] Expect that modified TestDependencies can't start clatd.
-        // Use precise check to make sure that there is no unexpected file descriptor closing.
         clearInvocations(TUN_PFD, RAW_SOCK_PFD, PACKET_SOCK_PFD);
-        assertNotStartClat(deps);
+
+        // [1] Expect that modified TestDependencies can't start clatd.
+        // Expect that the injection function of TestDependencies causes clatStart() failed.
+        final ClatCoordinator coordinatorWithBrokenDeps = new ClatCoordinator(deps);
+        assertThrows(IOException.class,
+                () -> coordinatorWithBrokenDeps.clatStart(BASE_IFACE, NETID, NAT64_IP_PREFIX));
+
+        // Use precise check to make sure that there is no unexpected file descriptor closing.
         if (needToCloseTunFd) {
             verify(TUN_PFD).close();
         } else {
@@ -583,10 +586,15 @@
             verify(RAW_SOCK_PFD, never()).close();
         }
 
+        // Check that dump doesn't crash after any clat starting failure.
+        verifyDump(coordinatorWithBrokenDeps, false /* clatStarted */);
+
         // [2] Expect that unmodified TestDependencies can start clatd.
         // Used to make sure that the above modified TestDependencies has really broken the
         // clatd starting.
-        assertStartClat(new TestDependencies());
+        final ClatCoordinator coordinatorWithDefaultDeps = new ClatCoordinator(
+                new TestDependencies());
+        assertNotNull(coordinatorWithDefaultDeps.clatStart(BASE_IFACE, NETID, NAT64_IP_PREFIX));
     }
 
     // The following testNotStartClat* tests verifies bunches of code for unwinding the