You can't change a message you've already sent, but you can switch how future messages send

Once a text message leaves your phone, it's delivered as either a regular SMS text or an iMessage — and you cannot convert one type to the other after the fact. What you can do is change the settings that control which type your iPhone uses going forward, or resend a conversation using a different method.

The difference matters because iMessages send over data or WiFi and show in blue bubbles, while SMS texts use your carrier's network and show in green bubbles. iMessages let you see when someone is typing and when they've read your message. SMS texts don't have those features. If you want future messages to a specific person to send as iMessage instead of SMS (or vice versa), you'll need to adjust your iPhone settings or start a new conversation thread.

Key Takeaways

  • Messages already sent cannot be changed from SMS to iMessage or back — the type is set the moment they leave your phone.
  • Turn iMessage on or off in Settings > Messages > iMessage to control which type your iPhone uses by default for all contacts.
  • If iMessage is on but a specific contact's messages send as SMS, that person likely doesn't have iMessage, or their device is unreachable.
  • Deleting a conversation thread and starting fresh sometimes forces your iPhone to re-evaluate which sending method to use.
  • You can manually choose SMS or iMessage for a single message by pressing and holding the message before you send it.

Turn iMessage on or off in your iPhone settings

The main control for whether your iPhone sends iMessages or SMS texts lives in the Messages app settings. Open Settings on your home screen, scroll down and tap Messages, then look for the iMessage toggle at the top. If the toggle is green and switched to the right, iMessage is on — your iPhone will send iMessages to other Apple device users and SMS to everyone else. If the toggle is gray and switched to the left, iMessage is off — all your messages will send as SMS texts.

Turning iMessage off means every message sends as a regular text, which uses your carrier's SMS network. This can be useful if you're having trouble with iMessage delivery or if you're switching to a non-Apple phone soon. Turning iMessage on means your iPhone will automatically detect whether the person you're texting has an Apple device and send iMessage to them, or SMS if they don't.

After you toggle iMessage on or off, give your phone a moment to sync with Apple's servers. New messages you send should reflect the change within a few seconds.

Why a specific contact's messages still send as SMS even with iMessage on

If iMessage is turned on but your messages to one particular person keep sending as SMS (green bubbles), it usually means that person's device is not registered with Apple's iMessage system, or their device is currently unreachable. This can happen if they have an older iPhone that doesn't support iMessage, if they switched to Android, if their iMessage is turned off, or if their device is offline.

You can't force an iMessage to send to someone who isn't registered. Your iPhone will automatically fall back to SMS. The only way to send iMessage to that person is if they turn iMessage on and their device registers with Apple's system.

If you believe the person should have iMessage but their messages are still green, ask them to check their own Settings > Messages > iMessage toggle. They may have turned it off without realizing it.

Delete and restart a conversation to reset the message type

Sometimes your iPhone gets stuck using SMS for a contact even though they have iMessage. Deleting the entire conversation thread and starting fresh can force your phone to re-evaluate which sending method to use. Open the Messages app, swipe left on the conversation with that contact, tap Delete, then confirm.

After you delete the thread, send a new message to that contact. Your iPhone will check whether they have iMessage available and choose the appropriate sending method. The new conversation should start fresh with the correct message type.

This step doesn't always work, but it's worth trying before you assume the other person doesn't have iMessage. Some users report that restarting their iPhone after deleting the thread makes the fix stick.

Manually choose SMS or iMessage for a single message

If you want to send one specific message as SMS even though iMessage is on, or as iMessage even though SMS is the default for that contact, you can override the setting for just that message. Type your message in the compose field, then press and hold the blue send button (the arrow icon) until a menu appears with options like "Send as Text Message" or "Send as iMessage."

Tap the option you want. That single message will send using your chosen method, but future messages to that contact will go back to whatever your default setting is. This is useful if you're having trouble with one message and want to try a different route, or if you're testing whether someone has iMessage working.

Check your Apple ID and phone number settings

iMessage relies on your Apple ID and your phone number to work. If your Apple ID is signed out of Messages, or if your phone number isn't registered with iMessage, your messages may not send as iMessage even though the toggle is on. Open Settings > Messages and scroll down to find "Send & Receive." Tap it and make sure your Apple ID is listed and your phone number is checked.

If your Apple ID isn't showing, tap "Use your Apple ID for iMessage," sign in with your credentials, and wait for your phone to register with Apple's servers. If your phone number isn't checked, tap it to enable it. After you make these changes, new messages should send as iMessage to other Apple users.

Restart your iPhone if messages won't switch types

If you've toggled iMessage on or off but messages still aren't sending the way you expect, a restart often clears up the problem. Hold down the power button and volume down button together until the "slide to power off" screen appears, then slide to turn off your phone. Wait 10 seconds, then press the power button to turn it back on.

After your iPhone restarts, open Messages and send a test message. Your phone should now use the sending method you selected. Restarting gives your iPhone time to re-sync with Apple's iMessage servers and your carrier's SMS network.

Frequently Asked Questions

Can I change a message from green to blue after I've sent it?

No. Once a message sends, its type is permanent. You cannot edit or convert it. If you need to resend a message as a different type, delete the original and send a new one, using the press-and-hold method to choose SMS or iMessage.

Why do some messages to the same person send as blue and others as green?

Your iPhone chooses the sending method based on whether it can reach the recipient's iMessage server at that moment. If their device is offline or iMessage is temporarily unavailable, a message may send as SMS instead. When their device comes back online, the next message may send as iMessage again.

If I turn off iMessage, will old iMessages still show in my conversation?

Yes. Turning iMessage off only affects new messages going forward. All your old iMessages and SMS texts will stay in the conversation thread. You can read them anytime, but new messages you send will be SMS only.

Does switching from iMessage to SMS cost money?

SMS texts may count against your carrier's text message plan if you have a limited number of texts per month. iMessages send over data or WiFi and don't count as SMS texts. Check your carrier's plan to see whether you have unlimited texts or a limit.

What if I'm switching to Android — do I need to turn off iMessage first?

Yes. If you switch to Android while iMessage is still on, people with iPhones may send you iMessages that you won't receive, because Android phones can't receive iMessages. Before you switch phones, turn off iMessage in Settings > Messages, or go to Apple's iMessage deregistration website and remove your phone number from the system.