Why Disable the SMS Fallback Feature?
Apple’s Messages app seamlessly handles two entirely different types of communication: iMessage (the blue bubbles) and standard SMS/MMS text messages (the green bubbles). iMessages are sent over the internet using Wi-Fi or cellular data, which is usually free and unlimited. SMS messages are sent through your cellular carrier’s legacy text messaging system. By default, if an iMessage fails to send because you have poor internet connectivity, iOS will automatically convert the message into an SMS text and send it anyway. This “Send as SMS” fallback feature can become a significant problem if you are traveling internationally, sending high-resolution photos, or texting a group, as those automatic green bubble fallbacks could result in unexpected and massive per-message carrier charges.
How to Turn Off “Send as SMS”
To ensure that your iPhone only ever attempts to send rich messages over the free iMessage network, you must disable the automatic SMS fallback toggle.
- Open the Settings app on your iPhone.
- Scroll down the main settings list until you locate the Messages app icon. Tap it.
- Scroll down to the middle of the Messages settings page.
- Locate the toggle switch labeled Send as SMS. (The description below it reads “Send as SMS when iMessage is unavailable. Carrier messaging rates may apply”).
- Tap the switch to turn it Off (the green background will disappear).
What Happens When a Message Fails Now?
With this setting disabled, your iPhone will no longer automatically convert failed internet messages into carrier texts. If you are in a location with terrible Wi-Fi and no cellular data, and you attempt to send an iMessage, it will simply fail. You will see a red exclamation point icon next to the blue bubble, indicating “Not Delivered.” The message will safely wait in your outbox until you regain a stable internet connection, guaranteeing you will never incur accidental SMS roaming fees. (Note: You can still manually tap a failed message and choose “Send as Text Message” if it is an emergency).