diff --git a/feature/registration/src/main/java/org/signal/registration/screens/phonenumber/PhoneNumberEntryScreen.kt b/feature/registration/src/main/java/org/signal/registration/screens/phonenumber/PhoneNumberEntryScreen.kt
index 7219360b4c..129fcc9080 100644
--- a/feature/registration/src/main/java/org/signal/registration/screens/phonenumber/PhoneNumberEntryScreen.kt
+++ b/feature/registration/src/main/java/org/signal/registration/screens/phonenumber/PhoneNumberEntryScreen.kt
@@ -59,7 +59,6 @@ import org.signal.core.ui.compose.DropdownMenus
 import org.signal.core.ui.compose.IconButtons.IconButton
 import org.signal.core.ui.compose.Previews
 import org.signal.core.ui.rememberWindowBreakpoint
-import org.signal.core.util.E164Util
 import org.signal.registration.R
 import org.signal.registration.screens.RegistrationScreen
 import org.signal.registration.screens.phonenumber.PhoneNumberEntryState.OneTimeEvent
@@ -81,7 +80,7 @@ fun PhoneNumberScreen(
   if (state.showDialog) {
     Dialogs.SimpleAlertDialog(
       title = stringResource(R.string.RegistrationActivity_is_the_phone_number),
-      body = "${E164Util.formatAsE164WithCountryCodeForDisplay(state.countryCode, state.nationalNumber)}\n\n${stringResource(R.string.RegistrationActivity_a_verification_code)}",
+      body = "+${state.countryCode} ${state.formattedNumber}\n\n${stringResource(R.string.RegistrationActivity_a_verification_code)}",
       confirm = stringResource(id = android.R.string.ok),
       dismiss = stringResource(R.string.RegistrationActivity_edit_number),
       onConfirm = { onEvent(PhoneNumberEntryScreenEvents.PhoneNumberSubmitted) },
@@ -397,7 +396,7 @@ private fun NextButton(
     } else {
       Buttons.LargeTonal(
         onClick = { onEvent(PhoneNumberEntryScreenEvents.PhoneNumberEntered) },
-        enabled = state.countryCode.isNotEmpty() && state.nationalNumber.isNotEmpty(),
+        enabled = state.isNumberPossible,
         modifier = Modifier.testTag(TestTags.PHONE_NUMBER_NEXT_BUTTON)
       ) {
         Text(stringResource(R.string.RegistrationActivity_next))
diff --git a/feature/registration/src/main/java/org/signal/registration/screens/phonenumber/PhoneNumberEntryState.kt b/feature/registration/src/main/java/org/signal/registration/screens/phonenumber/PhoneNumberEntryState.kt
index f76202ae86..3b339c6a4d 100644
--- a/feature/registration/src/main/java/org/signal/registration/screens/phonenumber/PhoneNumberEntryState.kt
+++ b/feature/registration/src/main/java/org/signal/registration/screens/phonenumber/PhoneNumberEntryState.kt
@@ -5,6 +5,8 @@
 
 package org.signal.registration.screens.phonenumber
 
+import com.google.i18n.phonenumbers.NumberParseException
+import com.google.i18n.phonenumbers.PhoneNumberUtil
 import org.signal.registration.NetworkController
 import org.signal.registration.NetworkController.SessionMetadata
 import org.signal.registration.PendingRestoreOption
@@ -36,4 +38,15 @@ data class PhoneNumberEntryState(
     data object UnableToSendSms : OneTimeEvent
     data object CouldNotRequestCodeWithSelectedTransport : OneTimeEvent
   }
+
+  val isNumberPossible: Boolean
+    get() {
+      if (countryCode.isEmpty() || nationalNumber.isEmpty()) return false
+      return try {
+        val number = PhoneNumberUtil.getInstance().parse("+$countryCode$nationalNumber", null)
+        PhoneNumberUtil.getInstance().isPossibleNumber(number)
+      } catch (_: NumberParseException) {
+        false
+      }
+    }
 }