diff --git a/transport/transport-backend-cct/src/main/java/com/google/android/datatransport/cct/CctTransportBackend.java b/transport/transport-backend-cct/src/main/java/com/google/android/datatransport/cct/CctTransportBackend.java
index c387a34a9ef..8c1ae0ae10b 100644
--- a/transport/transport-backend-cct/src/main/java/com/google/android/datatransport/cct/CctTransportBackend.java
+++ b/transport/transport-backend-cct/src/main/java/com/google/android/datatransport/cct/CctTransportBackend.java
@@ -27,6 +27,7 @@
 import com.google.android.datatransport.cct.proto.LogResponse;
 import com.google.android.datatransport.cct.proto.NetworkConnectionInfo;
 import com.google.android.datatransport.cct.proto.NetworkConnectionInfo.MobileSubtype;
+import com.google.android.datatransport.cct.proto.NetworkConnectionInfo.NetworkType;
 import com.google.android.datatransport.cct.proto.QosTierConfiguration;
 import com.google.android.datatransport.runtime.EventInternal;
 import com.google.android.datatransport.runtime.backends.BackendRequest;
@@ -65,6 +66,9 @@ final class CctTransportBackend implements TransportBackend {
   private static final String CONTENT_TYPE_HEADER_KEY = "Content-Type";
   private static final String PROTOBUF_CONTENT_TYPE = "application/x-protobuf";
 
+  @VisibleForTesting static final String KEY_NETWORK_TYPE = "net-type";
+  @VisibleForTesting static final String KEY_MOBILE_SUBTYPE = "mobile-subtype";
+
   private static final String KEY_SDK_VERSION = "sdk-version";
   private static final String KEY_MODEL = "model";
   private static final String KEY_HARDWARE = "hardware";
@@ -73,8 +77,6 @@ final class CctTransportBackend implements TransportBackend {
   private static final String KEY_OS_BUILD = "os-uild";
   private static final String KEY_MANUFACTURER = "manufacturer";
   private static final String KEY_FINGERPRINT = "fingerprint";
-  private static final String KEY_NETWORK_TYPE = "net-type";
-  private static final String KEY_MOBILE_SUBTYPE = "mobile-subtype";
   private static final String KEY_TIMEZONE_OFFSET = "tz-offset";
 
   private final ConnectivityManager connectivityManager;
@@ -125,12 +127,25 @@ public EventInternal decorate(EventInternal eventInternal) {
         .addMetadata(KEY_MANUFACTURER, Build.MANUFACTURER)
         .addMetadata(KEY_FINGERPRINT, Build.FINGERPRINT)
         .addMetadata(KEY_TIMEZONE_OFFSET, getTzOffset())
-        .addMetadata(KEY_NETWORK_TYPE, networkInfo.getType())
-        .addMetadata(KEY_MOBILE_SUBTYPE, toSubtypeValue(networkInfo.getSubtype()))
+        .addMetadata(KEY_NETWORK_TYPE, getNetTypeValue(networkInfo))
+        .addMetadata(KEY_MOBILE_SUBTYPE, getNetSubtypeValue(networkInfo))
         .build();
   }
 
-  private int toSubtypeValue(int subtype) {
+  private static int getNetTypeValue(NetworkInfo networkInfo) {
+    // when the device is not connected networkInfo returned by ConnectivityManger is null.
+    if (networkInfo == null) {
+      return NetworkType.NONE_VALUE;
+    }
+    return networkInfo.getType();
+  }
+
+  private static int getNetSubtypeValue(NetworkInfo networkInfo) {
+    // when the device is not connected networkInfo returned by ConnectivityManger is null.
+    if (networkInfo == null) {
+      return MobileSubtype.UNKNOWN_MOBILE_SUBTYPE_VALUE;
+    }
+    int subtype = networkInfo.getSubtype();
     if (subtype == -1) {
       return MobileSubtype.COMBINED_VALUE;
     }
diff --git a/transport/transport-backend-cct/src/test/java/com/google/android/datatransport/cct/CctTransportBackendTest.java b/transport/transport-backend-cct/src/test/java/com/google/android/datatransport/cct/CctTransportBackendTest.java
index b0d3b5f8d4f..4e307617674 100644
--- a/transport/transport-backend-cct/src/test/java/com/google/android/datatransport/cct/CctTransportBackendTest.java
+++ b/transport/transport-backend-cct/src/test/java/com/google/android/datatransport/cct/CctTransportBackendTest.java
@@ -23,6 +23,7 @@
 import static com.github.tomakehurst.wiremock.client.WireMock.verify;
 import static com.google.android.datatransport.cct.CctTransportBackend.getTzOffset;
 import static com.google.android.datatransport.cct.ProtoMatchers.protoMatcher;
+import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertEquals;
 
 import android.content.Context;
@@ -47,6 +48,9 @@
 import org.junit.runner.RunWith;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+import org.robolectric.annotation.Implementation;
+import org.robolectric.annotation.Implements;
 
 @RunWith(RobolectricTestRunner.class)
 public class CctTransportBackendTest {
@@ -205,4 +209,59 @@ public void send_whenBackendResponseTimesOut_shouldReturnTransientError() {
 
     assertEquals(response, BackendResponse.transientError());
   }
+
+  @Test
+  public void decorate_whenOnline_shouldProperlyPopulateNetworkInfo() {
+    CctTransportBackend backend =
+        new CctTransportBackend(
+            RuntimeEnvironment.application, TEST_ENDPOINT, wallClock, uptimeClock, 300);
+
+    EventInternal result =
+        backend.decorate(
+            EventInternal.builder()
+                .setEventMillis(INITIAL_WALL_TIME)
+                .setUptimeMillis(INITIAL_UPTIME)
+                .setTransportName("3")
+                .setPayload(PAYLOAD.toByteArray())
+                .build());
+
+    assertThat(result.get(CctTransportBackend.KEY_NETWORK_TYPE))
+        .isEqualTo(String.valueOf(NetworkConnectionInfo.NetworkType.MOBILE_VALUE));
+    assertThat(result.get(CctTransportBackend.KEY_MOBILE_SUBTYPE))
+        .isEqualTo(String.valueOf(NetworkConnectionInfo.MobileSubtype.EDGE_VALUE));
+  }
+
+  @Test
+  @Config(shadows = {OfflineConnectivityManagerShadow.class})
+  public void decorate_whenOffline_shouldProperlyPopulateNetworkInfo() {
+    CctTransportBackend backend =
+        new CctTransportBackend(
+            RuntimeEnvironment.application, TEST_ENDPOINT, wallClock, uptimeClock, 300);
+
+    EventInternal result =
+        backend.decorate(
+            EventInternal.builder()
+                .setEventMillis(INITIAL_WALL_TIME)
+                .setUptimeMillis(INITIAL_UPTIME)
+                .setTransportName("3")
+                .setPayload(PAYLOAD.toByteArray())
+                .build());
+
+    assertThat(result.get(CctTransportBackend.KEY_NETWORK_TYPE))
+        .isEqualTo(String.valueOf(NetworkConnectionInfo.NetworkType.NONE_VALUE));
+    assertThat(result.get(CctTransportBackend.KEY_MOBILE_SUBTYPE))
+        .isEqualTo(
+            String.valueOf(NetworkConnectionInfo.MobileSubtype.UNKNOWN_MOBILE_SUBTYPE_VALUE));
+  }
+
+  // When there is no active network, the ConnectivityManager returns null when
+  // getActiveNetworkInfo() is called.
+  @Implements(ConnectivityManager.class)
+  public static class OfflineConnectivityManagerShadow {
+
+    @Implementation
+    public NetworkInfo getActiveNetworkInfo() {
+      return null;
+    }
+  }
 }