diff --git a/telecomm/java/android/telecom/Phone.java b/telecomm/java/android/telecom/Phone.java
index 02bd0010de99e..bc0a146673073 100644
--- a/telecomm/java/android/telecom/Phone.java
+++ b/telecomm/java/android/telecom/Phone.java
@@ -23,6 +23,8 @@ import android.os.Build;
 import android.os.Bundle;
 import android.util.ArrayMap;
 
+import com.android.internal.annotations.GuardedBy;
+
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -115,6 +117,7 @@ public final class Phone {
     public static final int SDK_VERSION_R = 30;
 
     // A Map allows us to track each Call by its Telecom-specified call ID
+    @GuardedBy("mLock")
     private final Map<String, Call> mCallByTelecomCallId = new ArrayMap<>();
 
     // A List allows us to keep the Calls in a stable iteration order so that casually developed
@@ -154,7 +157,7 @@ public final class Phone {
             return;
         }
 
-        Call call = mCallByTelecomCallId.get(parcelableCall.getId());
+        Call call = getCallById(parcelableCall.getId());
         if (call == null) {
             call = new Call(this, parcelableCall.getId(), mInCallAdapter,
                     parcelableCall.getState(), mCallingPackage, mTargetSdkVersion);
@@ -191,14 +194,14 @@ public final class Phone {
         if (mTargetSdkVersion < SDK_VERSION_R
                 && parcelableCall.getState() == Call.STATE_AUDIO_PROCESSING) {
             Log.i(this, "removing audio processing call during update for sdk compatibility");
-            Call call = mCallByTelecomCallId.get(parcelableCall.getId());
+            Call call = getCallById(parcelableCall.getId());
             if (call != null) {
                 internalRemoveCall(call);
             }
             return;
         }
 
-        Call call = mCallByTelecomCallId.get(parcelableCall.getId());
+        Call call = getCallById(parcelableCall.getId());
         if (call != null) {
             checkCallTree(parcelableCall);
             call.internalUpdate(parcelableCall, mCallByTelecomCallId);
@@ -215,8 +218,14 @@ public final class Phone {
         }
     }
 
+    Call getCallById(String callId) {
+        synchronized (mLock) {
+            return mCallByTelecomCallId.get(callId);
+        }
+    }
+
     final void internalSetPostDialWait(String telecomId, String remaining) {
-        Call call = mCallByTelecomCallId.get(telecomId);
+        Call call = getCallById(telecomId);
         if (call != null) {
             call.internalSetPostDialWait(remaining);
         }
@@ -230,7 +239,7 @@ public final class Phone {
     }
 
     final Call internalGetCallByTelecomId(String telecomId) {
-        return mCallByTelecomCallId.get(telecomId);
+        return getCallById(telecomId);
     }
 
     final void internalBringToForeground(boolean showDialpad) {
@@ -249,35 +258,35 @@ public final class Phone {
     }
 
     final void internalOnConnectionEvent(String telecomId, String event, Bundle extras) {
-        Call call = mCallByTelecomCallId.get(telecomId);
+        Call call = getCallById(telecomId);
         if (call != null) {
             call.internalOnConnectionEvent(event, extras);
         }
     }
 
     final void internalOnRttUpgradeRequest(String callId, int requestId) {
-        Call call = mCallByTelecomCallId.get(callId);
+        Call call = getCallById(callId);
         if (call != null) {
             call.internalOnRttUpgradeRequest(requestId);
         }
     }
 
     final void internalOnRttInitiationFailure(String callId, int reason) {
-        Call call = mCallByTelecomCallId.get(callId);
+        Call call = getCallById(callId);
         if (call != null) {
             call.internalOnRttInitiationFailure(reason);
         }
     }
 
     final void internalOnHandoverFailed(String callId, int error) {
-        Call call = mCallByTelecomCallId.get(callId);
+        Call call = getCallById(callId);
         if (call != null) {
             call.internalOnHandoverFailed(error);
         }
     }
 
     final void internalOnHandoverComplete(String callId) {
-        Call call = mCallByTelecomCallId.get(callId);
+        Call call = getCallById(callId);
         if (call != null) {
             call.internalOnHandoverComplete();
         }