diff --git a/src/com/android/phone/VoicemailStatus.java b/src/com/android/phone/VoicemailStatus.java
index c5cd52c..4d7d388 100644
--- a/src/com/android/phone/VoicemailStatus.java
+++ b/src/com/android/phone/VoicemailStatus.java
@@ -16,6 +16,7 @@
 
 package com.android.phone;
 
+import android.annotation.Nullable;
 import android.content.ContentResolver;
 import android.content.ContentValues;
 import android.content.Context;
@@ -23,14 +24,16 @@
 import android.provider.VoicemailContract;
 import android.provider.VoicemailContract.Status;
 import android.telecom.PhoneAccountHandle;
-import com.android.phone.vvm.omtp.utils.PhoneAccountHandleConverter;
+import com.android.phone.vvm.omtp.VvmLog;
 
 public class VoicemailStatus {
 
+    private static final String TAG = "VvmStatus";
 
     public static class Editor {
 
         private final Context mContext;
+        @Nullable
         private final PhoneAccountHandle mPhoneAccountHandle;
 
         private ContentValues mValues = new ContentValues();
@@ -38,8 +41,13 @@
         private Editor(Context context, PhoneAccountHandle phoneAccountHandle) {
             mContext = context;
             mPhoneAccountHandle = phoneAccountHandle;
+            if (mPhoneAccountHandle == null) {
+                VvmLog.w(TAG, "VoicemailStatus.Editor created with null phone account, status will"
+                        + " not be written");
+            }
         }
 
+        @Nullable
         public PhoneAccountHandle getPhoneAccountHandle() {
             return mPhoneAccountHandle;
         }
@@ -76,6 +84,9 @@
         }
 
         public void apply() {
+            if (mPhoneAccountHandle == null) {
+                return;
+            }
             mValues.put(Status.PHONE_ACCOUNT_COMPONENT_NAME,
                     mPhoneAccountHandle.getComponentName().flattenToString());
             mValues.put(Status.PHONE_ACCOUNT_ID, mPhoneAccountHandle.getId());
@@ -116,23 +127,20 @@
         return new Editor(context, phoneAccountHandle);
     }
 
-    public static Editor edit(Context context, int subId) {
-        return new Editor(context, PhoneAccountHandleConverter.fromSubId(subId));
-    }
-
     /**
      * Reset the status to the "disabled" state, which the UI should not show anything for this
      * subId.
      */
-    public static void disable(Context context, int subId) {
-        edit(context, subId)
+    public static void disable(Context context, PhoneAccountHandle phoneAccountHandle) {
+        edit(context, phoneAccountHandle)
                 .setConfigurationState(Status.CONFIGURATION_STATE_NOT_CONFIGURED)
                 .setDataChannelState(Status.DATA_CHANNEL_STATE_NO_CONNECTION)
                 .setNotificationChannelState(Status.NOTIFICATION_CHANNEL_STATE_NO_CONNECTION)
                 .apply();
     }
 
-    public static DeferredEditor deferredEdit(Context context, int subId) {
-        return new DeferredEditor(context, PhoneAccountHandleConverter.fromSubId(subId));
+    public static DeferredEditor deferredEdit(Context context,
+            PhoneAccountHandle phoneAccountHandle) {
+        return new DeferredEditor(context, phoneAccountHandle);
     }
 }
diff --git a/src/com/android/phone/vvm/omtp/ActivationTask.java b/src/com/android/phone/vvm/omtp/ActivationTask.java
index aa262c0..716140c 100644
--- a/src/com/android/phone/vvm/omtp/ActivationTask.java
+++ b/src/com/android/phone/vvm/omtp/ActivationTask.java
@@ -126,19 +126,25 @@
         Assert.isNotMainThread();
         int subId = getSubId();
 
+        PhoneAccountHandle phoneAccountHandle = PhoneAccountHandleConverter.fromSubId(subId);
+        if (phoneAccountHandle == null) {
+            // This should never happen
+            VvmLog.e(TAG, "null phone account for subId " + subId);
+            return;
+        }
+
         OmtpVvmCarrierConfigHelper helper = new OmtpVvmCarrierConfigHelper(getContext(), subId);
         if (!helper.isValid()) {
             VvmLog.i(TAG, "VVM not supported on subId " + subId);
-            VoicemailStatus.disable(getContext(), subId);
+            VoicemailStatus.disable(getContext(), phoneAccountHandle);
             return;
         }
-        PhoneAccountHandle phoneAccountHandle = PhoneAccountHandleConverter.fromSubId(subId);
         if (!OmtpVvmSourceManager.getInstance(getContext())
                 .isVvmSourceRegistered(phoneAccountHandle)) {
             // Only show the "activating" message if activation has not been completed before in
             // this boot. Subsequent activations are more of a status check and usually does not
             // concern the user.
-            helper.handleEvent(VoicemailStatus.edit(getContext(), subId),
+            helper.handleEvent(VoicemailStatus.edit(getContext(), phoneAccountHandle),
                     OmtpEvents.CONFIG_ACTIVATING);
         }
 
diff --git a/src/com/android/phone/vvm/omtp/OmtpVvmCarrierConfigHelper.java b/src/com/android/phone/vvm/omtp/OmtpVvmCarrierConfigHelper.java
index 5d06d1e..b4fbb3f 100644
--- a/src/com/android/phone/vvm/omtp/OmtpVvmCarrierConfigHelper.java
+++ b/src/com/android/phone/vvm/omtp/OmtpVvmCarrierConfigHelper.java
@@ -135,9 +135,13 @@
         return mSubId;
     }
 
+    @Nullable
     public PhoneAccountHandle getPhoneAccountHandle() {
         if (mPhoneAccountHandle == null) {
             mPhoneAccountHandle = PhoneAccountHandleConverter.fromSubId(mSubId);
+            if (mPhoneAccountHandle == null) {
+                VvmLog.e(TAG, "null phone account for subId " + mSubId);
+            }
         }
         return mPhoneAccountHandle;
     }
@@ -305,7 +309,13 @@
     }
 
     public void startActivation() {
-        VoicemailStatus.edit(mContext, mSubId)
+        PhoneAccountHandle phoneAccountHandle = getPhoneAccountHandle();
+        if (phoneAccountHandle == null) {
+            // This should never happen
+            // Error logged in getPhoneAccountHandle().
+            return;
+        }
+        VoicemailStatus.edit(mContext, phoneAccountHandle)
                 .setType(getVvmType())
                 .apply();
 
diff --git a/src/com/android/phone/vvm/omtp/SimChangeReceiver.java b/src/com/android/phone/vvm/omtp/SimChangeReceiver.java
index ea7dfa6..25c27db 100644
--- a/src/com/android/phone/vvm/omtp/SimChangeReceiver.java
+++ b/src/com/android/phone/vvm/omtp/SimChangeReceiver.java
@@ -66,7 +66,7 @@
                 int subId = intent.getIntExtra(PhoneConstants.SUBSCRIPTION_KEY,
                         SubscriptionManager.INVALID_SUBSCRIPTION_ID);
 
-                if (subId == SubscriptionManager.INVALID_SUBSCRIPTION_ID) {
+                if (!SubscriptionManager.isValidSubscriptionId(subId)) {
                     VvmLog.i(TAG, "Received SIM change for invalid subscription id.");
                     return;
                 }
@@ -83,11 +83,16 @@
     }
 
     public static void processSubId(Context context, int subId) {
+        PhoneAccountHandle phoneAccount = PhoneAccountHandleConverter.fromSubId(subId);
+        if (phoneAccount == null) {
+            // This should never happen
+            VvmLog.e(TAG, "unable to convert subId " + subId + " to PhoneAccountHandle");
+            return;
+        }
+
         OmtpVvmCarrierConfigHelper carrierConfigHelper =
                 new OmtpVvmCarrierConfigHelper(context, subId);
         if (carrierConfigHelper.isValid()) {
-            PhoneAccountHandle phoneAccount = PhoneAccountHandleConverter.fromSubId(subId);
-
             if (VisualVoicemailSettingsUtil.isEnabled(context, phoneAccount)) {
                 VvmLog.i(TAG, "Sim state or carrier config changed for " + subId);
                 // Add a phone state listener so that changes to the communication channels
@@ -110,7 +115,7 @@
             String mccMnc = context.getSystemService(TelephonyManager.class).getSimOperator(subId);
             VvmLog.d(TAG,
                     "visual voicemail not supported for carrier " + mccMnc + " on subId " + subId);
-            VoicemailStatus.disable(context, subId);
+            VoicemailStatus.disable(context, phoneAccount);
         }
     }
 
diff --git a/src/com/android/phone/vvm/omtp/VvmBootCompletedReceiver.java b/src/com/android/phone/vvm/omtp/VvmBootCompletedReceiver.java
index fe1f4cb..6bd7fa1 100644
--- a/src/com/android/phone/vvm/omtp/VvmBootCompletedReceiver.java
+++ b/src/com/android/phone/vvm/omtp/VvmBootCompletedReceiver.java
@@ -21,7 +21,7 @@
 import android.content.Intent;
 import android.telecom.PhoneAccountHandle;
 import android.telecom.TelecomManager;
-
+import android.telephony.SubscriptionManager;
 import com.android.phone.vvm.omtp.utils.PhoneAccountHandleConverter;
 
 /**
@@ -49,6 +49,12 @@
         for (PhoneAccountHandle handle : TelecomManager.from(context)
                 .getCallCapablePhoneAccounts()) {
             int subId = PhoneAccountHandleConverter.toSubId(handle);
+            if (!SubscriptionManager.isValidSubscriptionId(subId)) {
+                // b/30474294 getCallCapablePhoneAccounts() might return a PhoneAccountHandle with
+                // invalid subId if no SIM is inserted.
+                VvmLog.e(TAG, "phone account " + handle + " has invalid subId " + subId);
+                continue;
+            }
             VvmLog.v(TAG, "processing subId " + subId);
             SimChangeReceiver.processSubId(context, subId);
         }
diff --git a/src/com/android/phone/vvm/omtp/protocol/Vvm3EventHandler.java b/src/com/android/phone/vvm/omtp/protocol/Vvm3EventHandler.java
index 6fac708..d95879f 100644
--- a/src/com/android/phone/vvm/omtp/protocol/Vvm3EventHandler.java
+++ b/src/com/android/phone/vvm/omtp/protocol/Vvm3EventHandler.java
@@ -113,6 +113,12 @@
         OmtpEvents event) {
         switch (event) {
             case CONFIG_REQUEST_STATUS_SUCCESS:
+                if (status.getPhoneAccountHandle() == null) {
+                    // This should never happen.
+                    Log.e(TAG, "status editor has null phone account handle");
+                    return true;
+                }
+
                 if (!VoicemailChangePinActivity
                     .isDefaultOldPinSet(context, status.getPhoneAccountHandle())) {
                     return false;
diff --git a/src/com/android/phone/vvm/omtp/scheduling/RetryPolicy.java b/src/com/android/phone/vvm/omtp/scheduling/RetryPolicy.java
index bd0c75e..4f4126a 100644
--- a/src/com/android/phone/vvm/omtp/scheduling/RetryPolicy.java
+++ b/src/com/android/phone/vvm/omtp/scheduling/RetryPolicy.java
@@ -17,8 +17,10 @@
 package com.android.phone.vvm.omtp.scheduling;
 
 import android.content.Intent;
+import android.telecom.PhoneAccountHandle;
 import com.android.phone.VoicemailStatus;
 import com.android.phone.vvm.omtp.VvmLog;
+import com.android.phone.vvm.omtp.utils.PhoneAccountHandleConverter;
 
 /**
  * A task with this policy will automatically re-queue itself if {@link BaseTask#fail()} has been
@@ -67,8 +69,15 @@
                     + mRetryDelayMillis);
             mTask.setExecutionTime(mTask.getTimeMillis() + mRetryDelayMillis);
         }
-        mVoicemailStatusEditor = VoicemailStatus.deferredEdit(task.getContext(),
-                task.getSubId());
+        PhoneAccountHandle phoneAccountHandle = PhoneAccountHandleConverter
+                .fromSubId(task.getSubId());
+        if (phoneAccountHandle == null) {
+            VvmLog.e(TAG, "null phone account for subId " + task.getSubId());
+            // This should never happen, but continue on if it does. The status write will be
+            // discarded.
+        }
+        mVoicemailStatusEditor = VoicemailStatus
+                .deferredEdit(task.getContext(), phoneAccountHandle);
     }
 
     @Override
diff --git a/src/com/android/phone/vvm/omtp/sms/OmtpMessageReceiver.java b/src/com/android/phone/vvm/omtp/sms/OmtpMessageReceiver.java
index 7b4d2c3..0d49ebe 100644
--- a/src/com/android/phone/vvm/omtp/sms/OmtpMessageReceiver.java
+++ b/src/com/android/phone/vvm/omtp/sms/OmtpMessageReceiver.java
@@ -53,7 +53,8 @@
         PhoneAccountHandle phone = PhoneAccountHandleConverter.fromSubId(subId);
 
         if (phone == null) {
-            VvmLog.i(TAG, "Received message for null phone account");
+            // This should never happen
+            VvmLog.i(TAG, "Received message for null phone account on subId " + subId);
             return;
         }
 
diff --git a/src/com/android/phone/vvm/omtp/sync/UploadTask.java b/src/com/android/phone/vvm/omtp/sync/UploadTask.java
index fc28acf..87c0a46 100644
--- a/src/com/android/phone/vvm/omtp/sync/UploadTask.java
+++ b/src/com/android/phone/vvm/omtp/sync/UploadTask.java
@@ -20,6 +20,7 @@
 import android.content.Intent;
 import android.telecom.PhoneAccountHandle;
 import com.android.phone.VoicemailStatus;
+import com.android.phone.vvm.omtp.VvmLog;
 import com.android.phone.vvm.omtp.scheduling.BaseTask;
 import com.android.phone.vvm.omtp.scheduling.PostponePolicy;
 import com.android.phone.vvm.omtp.utils.PhoneAccountHandleConverter;
@@ -30,6 +31,8 @@
  */
 public class UploadTask extends BaseTask {
 
+    private static final String TAG = "VvmUploadTask";
+
     private static final int POSTPONE_MILLIS = 5_000;
 
     public UploadTask() {
@@ -52,8 +55,15 @@
     @Override
     public void onExecuteInBackgroundThread() {
         OmtpVvmSyncService service = new OmtpVvmSyncService(getContext());
+
+        PhoneAccountHandle phoneAccountHandle = PhoneAccountHandleConverter.fromSubId(getSubId());
+        if (phoneAccountHandle == null) {
+            // This should never happen
+            VvmLog.e(TAG, "null phone account for subId " + getSubId());
+            return;
+        }
         service.sync(this, OmtpVvmSyncService.SYNC_UPLOAD_ONLY,
-                PhoneAccountHandleConverter.fromSubId(getSubId()), null,
-                VoicemailStatus.edit(getContext(), getSubId()));
+                phoneAccountHandle, null,
+                VoicemailStatus.edit(getContext(), phoneAccountHandle));
     }
 }
diff --git a/src/com/android/phone/vvm/omtp/utils/PhoneAccountHandleConverter.java b/src/com/android/phone/vvm/omtp/utils/PhoneAccountHandleConverter.java
index 0474452..ad4c423 100644
--- a/src/com/android/phone/vvm/omtp/utils/PhoneAccountHandleConverter.java
+++ b/src/com/android/phone/vvm/omtp/utils/PhoneAccountHandleConverter.java
@@ -16,10 +16,13 @@
 
 package com.android.phone.vvm.omtp.utils;
 
+import android.annotation.Nullable;
 import android.telecom.PhoneAccountHandle;
 import android.telephony.SubscriptionManager;
-
+import com.android.internal.telephony.Phone;
+import com.android.internal.telephony.PhoneFactory;
 import com.android.phone.PhoneUtils;
+import com.android.phone.vvm.omtp.VvmLog;
 
 /**
  * Utility to convert between PhoneAccountHandle and subId, which is a common operation in OMTP
@@ -29,9 +32,22 @@
  */
 public class PhoneAccountHandleConverter {
 
+    private static final String TAG = "PhoneAccountHndCvtr";
+
+    @Nullable
     public static PhoneAccountHandle fromSubId(int subId) {
-        return PhoneUtils.makePstnPhoneAccountHandle(
-                SubscriptionManager.getPhoneId(subId));
+        if (!SubscriptionManager.isValidSubscriptionId(subId)) {
+            VvmLog.e(TAG, "invalid subId " + subId);
+            return null;
+        }
+        // Calling PhoneUtils.makePstnPhoneAccountHandle() with a phoneId might throw a NPE if the
+        // phone object cannot be found, so the Phone object should be created and checked here.
+        Phone phone = PhoneFactory.getPhone(SubscriptionManager.getPhoneId(subId));
+        if (phone == null) {
+            VvmLog.e(TAG, "Unable to find Phone for subId " + subId);
+            return null;
+        }
+        return PhoneUtils.makePstnPhoneAccountHandle(phone);
     }
 
     public static int toSubId(PhoneAccountHandle handle) {