diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/telephony/hlrlookup/HlrLookupCarrierDataProvider.java b/service/src/main/java/org/whispersystems/textsecuregcm/telephony/hlrlookup/HlrLookupCarrierDataProvider.java
index b080ee49e..4980dbe52 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/telephony/hlrlookup/HlrLookupCarrierDataProvider.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/telephony/hlrlookup/HlrLookupCarrierDataProvider.java
@@ -171,7 +171,7 @@ public class HlrLookupCarrierDataProvider implements CarrierDataProvider {
   static Optional<String> mncFromMccMnc(@Nullable final String mccMnc) {
     // MNCs may be 2 or 3 digits, but always come after a 3-digit MCC
     return Optional.ofNullable(StringUtils.stripToNull(mccMnc))
-        .map(trimmedMccMnc -> trimmedMccMnc.substring(3));
+        .map(trimmedMccMnc -> StringUtils.stripToNull(trimmedMccMnc.substring(3)));
   }
 
   @VisibleForTesting
diff --git a/service/src/test/java/org/whispersystems/textsecuregcm/telephony/hlrlookup/HlrLookupCarrierDataProviderTest.java b/service/src/test/java/org/whispersystems/textsecuregcm/telephony/hlrlookup/HlrLookupCarrierDataProviderTest.java
index fafb2dd53..bce0d6da6 100644
--- a/service/src/test/java/org/whispersystems/textsecuregcm/telephony/hlrlookup/HlrLookupCarrierDataProviderTest.java
+++ b/service/src/test/java/org/whispersystems/textsecuregcm/telephony/hlrlookup/HlrLookupCarrierDataProviderTest.java
@@ -187,7 +187,8 @@ class HlrLookupCarrierDataProviderTest {
         Arguments.argumentSet("Empty mccMnc string", "", Optional.empty()),
         Arguments.argumentSet("Blank mccMnc string", " ", Optional.empty()),
         Arguments.argumentSet("Two-digit MNC", "12345", Optional.of("123")),
-        Arguments.argumentSet("Three-digit MNC", "123456", Optional.of("123"))
+        Arguments.argumentSet("Three-digit MNC", "123456", Optional.of("123")),
+        Arguments.argumentSet("MCC-only", "123", Optional.of("123"))
     );
   }
 
@@ -204,7 +205,8 @@ class HlrLookupCarrierDataProviderTest {
         Arguments.argumentSet("Empty mccMnc string", "", Optional.empty()),
         Arguments.argumentSet("Blank mccMnc string", " ", Optional.empty()),
         Arguments.argumentSet("Two-digit MNC", "12345", Optional.of("45")),
-        Arguments.argumentSet("Three-digit MNC", "123456", Optional.of("456"))
+        Arguments.argumentSet("Three-digit MNC", "123456", Optional.of("456")),
+        Arguments.argumentSet("MCC-only", "123", Optional.empty())
     );
   }