iMessage is turned on in Settings, under Messages
iMessage is Apple's messaging service that sends texts over the internet instead of through your phone carrier. When iMessage is on, your messages to other Apple users travel through Apple's servers and show up in blue bubbles instead of green ones. Messages to non-Apple phones still go through your carrier as regular texts and show up in green.
On iPhone 15, iMessage is usually on by default when you set up the phone, but it can be turned off accidentally or by a setting change. To turn it back on, open the Settings app, tap Messages, and toggle iMessage to the on position (the switch will turn green).
The whole process takes about 30 seconds. You do not need to restart your phone or do anything else after you turn it on — it activates when ready.
Key Takeaways
- iMessage is enabled in Settings > Messages > iMessage, and the toggle switch should turn green when it is on.
- Your phone number and Apple ID are registered with iMessage automatically when you turn it on, so you do not need to enter them separately.
- Messages to other iPhone users will appear in blue bubbles once iMessage is on; messages to Android phones will still be green and use your carrier's text plan.
- If iMessage does not turn on, check that you have an internet connection and that your Apple ID is signed in under Settings > [Your Name].
Step-by-step: turning iMessage on
Open the Settings app on your home screen. Scroll down and tap Messages. At the top of the Messages screen, you will see a toggle switch next to "iMessage." If the switch is gray, iMessage is off. Tap the switch once to turn it on — it will turn green and move to the right.
Wait a few seconds for the phone to register your number and Apple ID with Apple's servers. You will see a small checkmark appear next to iMessage once registration is complete. After that, you can close Settings and start using iMessage.
What happens when iMessage is on
When iMessage is on, your iPhone automatically detects whether the person you are texting has an Apple device. If they do, the message goes through iMessage over the internet. If they do not, the message goes through your carrier as a regular text message and you are charged according to your phone plan (or your unlimited texting allowance, if you have one).
You will see the difference in the Messages app: iMessage conversations show blue bubbles with your messages, while regular text messages show green bubbles. At the top of a conversation, you will also see "iMessage" in small text if that person is using iMessage, or nothing if they are not.
iMessage works over WiFi or cellular data, so you do not need cell service to send an iMessage — only an internet connection. This is useful if you are in a place with WiFi but no cell signal.
Why iMessage might not turn on
The most common reason iMessage will not turn on is that your Apple ID is not signed in. Go to Settings > [Your Name] at the very top of the Settings app. If you see "Sign in to your iPhone," tap it and enter your Apple ID email and password. Once you are signed in, go back to Settings > Messages and try turning iMessage on again.
The second reason is no internet connection. iMessage needs WiFi or cellular data to register your number with Apple's servers. Make sure you are connected to WiFi or have cellular data turned on. If you are on WiFi, try disconnecting and reconnecting to the network, or restart your phone.
If iMessage still will not turn on after you have signed in and checked your internet, restart your iPhone. Hold down the side button and either volume button until the power-off slider appears. Drag it to turn off the phone, wait 10 seconds, then hold the side button again until the Apple logo appears.
The difference between iMessage and regular text messages
iMessage and regular SMS text messages are not the same thing, and your phone treats them differently. iMessage is encrypted end-to-end, meaning Apple cannot read your messages. Regular text messages sent through your carrier are not encrypted the same way. iMessage also lets you send photos, videos, and voice messages without using your carrier's data, and you can see when someone is typing.
The cost difference matters too. iMessage uses your internet connection, so it does not count against your text message limit or data plan (it uses a tiny amount of data, but not enough to matter). Regular text messages count against your carrier's limits. If you have unlimited texting, this does not affect you, but if you have a limited plan, iMessage saves you from using up your texts.
What to do if you want iMessage off
Some people turn iMessage off on purpose. If you are switching from iPhone to Android, you should turn iMessage off before you switch, because if you do not, text messages from iPhone users will still try to go through iMessage and you will not receive them on your Android phone. Go to Settings > Messages and toggle iMessage to off (the switch will turn gray).
You can also turn off iMessage for specific contacts if you want. In the Messages app, open a conversation, tap the contact's name at the top, scroll down, and toggle off "Send as iMessage." That person's messages will go through as regular texts from then on.
Frequently Asked Questions
Do I need to do anything after I turn iMessage on?
No. Once the toggle is green and you see the checkmark, iMessage is ready to use. Your phone number and Apple ID are registered automatically. You can close Settings and start texting right away.
Will turning iMessage on cost me money?
No. iMessage uses your internet connection, not your carrier's text plan. You do not pay per message. If you have a WiFi or data plan, iMessage is included at no extra cost.
Why are some of my messages green and some blue?
Green bubbles mean the person does not have an Apple device or does not have iMessage on, so your message went through as a regular text. Blue bubbles mean the person has iMessage on and your message went through Apple's servers instead.
Can I use iMessage without WiFi?
Yes. iMessage works over cellular data, so you can send messages anywhere you have cell service or WiFi. You do not need to be on WiFi specifically, just connected to the internet in some way.
What if I share an Apple ID with someone else on my phone?
iMessage will register to that shared Apple ID, and both of you will see each other's messages in the same conversation thread. If you want separate iMessage accounts, each person needs their own Apple ID on their own phone.