iMessage turns on automatically on most Apple devices, but you may need to check your settings or sign in with your Apple ID

iMessage is Apple's encrypted messaging service that works over Wi-Fi or cellular data instead of the SMS text network. If you own an iPhone, iPad, or Mac, iMessage is built in — you do not need to read anything. The service sends messages to other Apple users as iMessages (shown in blue bubbles) and falls back to regular text messages (green bubbles) when you message someone without an Apple device.

On a new iPhone, iMessage usually activates during setup when you sign in with your Apple ID. On older devices or if you switched from Android, you may need to turn it on manually in Settings. The process takes less than a minute and requires only your Apple ID and an active internet connection.

Key Takeaways

  • iMessage activates automatically during iPhone setup if you sign in with your Apple ID, but you can turn it on anytime in Settings > Messages.
  • You need an active Apple ID, Wi-Fi or cellular data, and a phone number or email address registered to your account to send iMessages.
  • Messages to other Apple users appear in blue and include read receipts and typing indicators; messages to non-Apple users appear in green and use standard SMS.
  • If you switched from Android, you may need to remove your phone number from Apple's iMessage registry to receive text messages from iPhone users.

Turning on iMessage in Settings on iPhone or iPad

Open the Settings app and tap Messages. Look for the toggle next to iMessage at the top of the screen. If the toggle is gray, tap it to turn iMessage on. The toggle will turn green and show On.

If you see a message saying "Waiting for set up" or a spinning circle, your device is connecting to Apple's servers. This usually takes a few seconds but can take up to a minute on slower connections. Do not close Settings during this time.

If the iMessage toggle does not appear or you see an error message, check that you are signed in to your Apple ID. Go to Settings > [Your Name] at the top of the screen. If you see "Sign in to your iPhone," tap it and enter your Apple ID email and password. Then return to Settings > Messages and try turning on iMessage again.

Turning on iMessage on Mac

Open the Messages app (located in Applications > Utilities or search for it using Spotlight). Click Messages in the menu bar at the top, then select Settings or Preferences depending on your macOS version. Click the Accounts tab.

Look for your Apple ID in the list on the left. If you do not see it, click the plus sign (+) at the bottom and sign in with your Apple ID. Once your account appears, make sure the checkbox next to it is checked. Close the Settings window — iMessage is now active on your Mac.

What happens when you switch to iMessage

Once iMessage is on, your Messages app will automatically route conversations based on the recipient's device. When you send a message to someone with an iPhone, iPad, or Mac, it sends as an iMessage over data and appears in a blue bubble on both your screen and theirs. You will see read receipts (showing when they read your message) and typing indicators (the three dots showing they are typing).

When you message someone with an Android phone or other non-Apple device, the message sends as a standard text message (SMS) and appears in a green bubble. These messages do not include read receipts or typing indicators, and they count against your text message plan if you have a limit.

You can see which type of message you are sending before you hit send — the send button shows Send for iMessage and Send for SMS, though the color of the bubble is the clearest indicator.

Registering your phone number and email with iMessage

When you turn on iMessage, Apple registers your phone number and any email addresses linked to your Apple ID. This lets other people reach you via iMessage using either your number or email. You can add or remove email addresses in Settings > Messages > Send & Receive (on iPhone) or Messages > Settings > Accounts (on Mac).

Your phone number is registered automatically and cannot be removed from iMessage settings, though you can change which number appears as your default sender. If you want to use only an email address for iMessage and not your phone number, you can set that in the same Send & Receive menu.

Switching from Android to iPhone and receiving text messages

If you recently switched from an Android phone to an iPhone, iPhone users may still try to send you iMessages that get stuck in Apple's system. This happens because your phone number was registered with iMessage on your old Android device. To fix this, you need to remove your number from Apple's iMessage registry.

Visit iMessage.com (Apple's deregistration page) on any web browser. Enter the phone number you used on your old Android phone. Apple will send a confirmation code to that number. Enter the code on the website to deregister. This usually takes a few minutes to process. After that, iPhone users will send you regular text messages instead of iMessages, and you will receive them normally on your new iPhone.

If you no longer have access to your old phone number, you can contact Apple Support through the same website to request manual deregistration. Have your new iPhone phone number and Apple ID ready.

Troubleshooting iMessage set up problems

If iMessage will not turn on or stays on "Waiting for set up," first check your internet connection. iMessage requires Wi-Fi or cellular data to set up, even though it can send messages over either connection. Try turning Wi-Fi off and on, or switch between Wi-Fi and cellular to see if that helps.

If set up still fails, sign out of your Apple ID and sign back in. Go to Settings > [Your Name] > Sign Out, enter your password, and then sign back in with the same Apple ID. Return to Settings > Messages and turn on iMessage again.

If you see an error message with a specific code, write down the code and check Apple's support site or contact Apple Support directly. Some errors relate to account issues or regional restrictions that require Apple's help to resolve.

Frequently Asked Questions

Do I need a separate app to use iMessage?

No. iMessage is built into the Messages app on iPhone, iPad, and Mac. You do not need to read anything. If you have an Apple device and sign in with your Apple ID, you already have access to iMessage.

Can I use iMessage without a phone number?

Yes. You can send and receive iMessages using only an email address registered to your Apple ID. On iPhone, go to Settings > Messages > Send & Receive and uncheck your phone number if you want to use email only. Other people can reach you by typing your email into their Messages app.

Why do my messages to a friend appear green instead of blue?

Green bubbles mean the recipient does not have an Apple device, or iMessage is turned off on their device. Messages sent to Android phones, Windows computers, or older devices without iMessage always appear green and send as standard text messages.

What if I turn off iMessage — can I turn it back on?

Yes. You can turn iMessage on and off anytime in Settings > Messages on iPhone or Messages > Settings on Mac. Turning it off does not delete your message history. When you turn it back on, all your previous conversations remain in the Messages app.

Does iMessage cost money?

No. iMessage is free to use. It sends messages over Wi-Fi or your cellular data plan, so it does not use text message credits if you have a limited plan. You only need an Apple ID and an active internet connection.