diff --git a/telephony/java/com/android/internal/telephony/gsm/GSMPhone.java b/telephony/java/com/android/internal/telephony/gsm/GSMPhone.java
index 43971ff09f790..3959c67748429 100644
--- a/telephony/java/com/android/internal/telephony/gsm/GSMPhone.java
+++ b/telephony/java/com/android/internal/telephony/gsm/GSMPhone.java
@@ -1223,7 +1223,8 @@ public class GSMPhone extends PhoneBase {
                 // Check if this is a different SIM than the previous one. If so unset the
                 // voice mail number.
                 String imsi = getVmSimImsi();
-                if (imsi != null && !getSubscriberId().equals(imsi)) {
+                String imsiFromSIM = getSubscriberId();
+                if (imsi != null && imsiFromSIM != null && !imsiFromSIM.equals(imsi)) {
                     storeVoiceMailNumber(null);
                     setVmSimImsi(null);
                 }