How to Turn SMS On or Off on iPhone and Android

On iPhone, SMS is always on; you control whether iMessage falls back to SMS. On Android, SMS lives in your messages app, with RCS chat as an extra.

iPhone

• Send as text when iMessage fails: Settings › Apps › Messages › Send as Text Message (on older iOS: Settings › Messages › Send as SMS).
• Stop using iMessage: turn off iMessage in the same screen; messages then go as SMS or RCS.
• RCS: on recent iOS versions there is an RCS Messaging switch in Messages settings where your carrier supports it.

Android (Google Messages)

• Use Messages as your SMS app: Settings › Apps › Default apps › SMS app.
• Turn chat features (RCS) on or off: Messages › Settings › RCS chats.
• Block texts from someone: open the conversation, tap the menu and choose Block.

You cannot fully switch off SMS

Text messaging is part of your mobile service. To stop receiving texts entirely you would need your carrier to block them, which also blocks verification codes. Blocking senders or filtering spam is usually what people want instead.

Filtering instead of switching off

If the real goal is fewer unwanted texts, filtering is better than turning anything off. iPhone can sort unknown senders into a separate list, and Android can move suspected spam aside. You keep receiving codes and messages from people you know, while the rest stays out of the main inbox.

FAQ

How do I make my iPhone send SMS instead of iMessage?

Turn off iMessage, or keep it on and turn on Send as Text Message for when iMessage fails.

How do I turn off RCS on Android?

Open Google Messages › Settings › RCS chats and turn it off.

Will turning off iMessage stop codes arriving?

No. Verification codes are sent as SMS.

Related: iMessage vs SMS · RCS vs SMS · block spam texts.