What iMessage is and why you might want to switch
iMessage is Apple's messaging system that runs over the internet instead of using your phone's text message plan. When you send an iMessage to another Apple device, the message travels through Apple's servers rather than through your carrier's network. On your iPhone, iMessages appear in blue bubbles in the Messages app, while regular text messages (called SMS or MMS) appear in green bubbles.
The main reason people switch to iMessage is that it works over WiFi or data, so you can message even without cell service. It also shows when someone is typing, lets you know when they've read your message, and handles photos and videos without the quality loss that sometimes happens with regular texts. If you're messaging other iPhone users, iMessage is usually faster and more reliable than regular texting.
The catch: iMessage only works between Apple devices. If you message an Android phone, you'll automatically drop back to regular text messages, which means you lose the read receipts and typing indicators for that conversation.
Key Takeaways
- iMessage turns on automatically on most iPhones when you sign in with your Apple ID, so you may already be using it without realizing.
- You can turn iMessage on or off in Settings > Messages > iMessage with a single toggle switch.
- iMessage uses your Apple ID and phone number to work, so you need both registered with Apple for it to function properly.
- If iMessage won't turn on, the most common fix is signing out of your Apple ID in Settings and signing back in.
How to turn on iMessage if it's off
Open Settings on your iPhone and tap Messages. Look for the iMessage toggle switch near the top of the screen. If it's gray, iMessage is off. Tap it once to turn it on — it will turn green and say "On".
Your iPhone will connect to Apple's servers using your Apple ID. This usually takes a few seconds. Once it's on, any messages you send to other iPhone, iPad, or Mac users will automatically go through iMessage instead of regular text. Messages to Android phones will still use regular text.
What you need for iMessage to work
iMessage requires two things: an active Apple ID and either your phone number or an email address registered with that ID. When you set up your iPhone, you usually sign in with your Apple ID automatically, so this is already done for most people.
To check what contact information is registered, go to Settings > Messages > Send & Receive. You'll see your Apple ID email and your phone number listed. If your phone number isn't there, tap "Use your Apple ID for iMessage" and follow the prompts to add it. Both your email and phone number should have checkmarks next to them.
Why iMessage might not turn on
The most common reason iMessage won't set up is that your Apple ID isn't properly connected to your iPhone. The fix is to sign out and sign back in: go to Settings > [Your Name] > Sign Out, enter your Apple ID password, then sign back in with the same Apple ID. This usually takes a minute or two.
A second common issue is that your carrier hasn't activated your phone number for messaging yet. If you just switched to a new phone or a new carrier, wait 24 hours before trying again. If it's been longer than that and iMessage still won't turn on, contact your carrier to confirm your phone number is active.
Occasionally a software glitch will prevent iMessage from connecting. Restart your iPhone by holding down the power button and sliding to power off, waiting 10 seconds, then turning it back on. Then try turning iMessage on again.
How to know if a message went through iMessage or regular text
Open the Messages app and look at the color of the message bubble. Blue bubbles mean iMessage — the message went through Apple's network. Green bubbles mean regular SMS or MMS text — the message went through your carrier. You'll also see "Delivered" under a blue iMessage and "Sent" under a green text message.
If you're messaging someone with an iPhone and you see green bubbles, it usually means their iMessage is turned off, or they're using an older iPhone that doesn't support iMessage. You can still message them, but you'll be charged for texts if you don't have unlimited texting in your plan.
Turning iMessage off if you don't want it
Go to Settings > Messages > iMessage and tap the toggle to turn it off. It will turn gray. All your messages will then go through regular text, even to other iPhone users. This uses your text message plan instead of data or WiFi.
Some people turn iMessage off if they're switching to Android soon and want to make sure their contacts' phones are ready to receive regular texts from them. Others turn it off if they're having trouble with iMessage delivery and want to troubleshoot by using regular text for a while.
What happens to old iMessages if you turn iMessage off
Your old iMessages stay in the Messages app and remain readable. Turning iMessage off only affects new messages you send going forward — those will be green texts instead of blue iMessages. The old blue message threads don't change or disappear.
If you turn iMessage back on later, new messages to iPhone users will be blue again, but the old green texts in that conversation will stay green. This is normal and doesn't affect how the messages work.
Frequently Asked Questions
Can I use iMessage on my iPad or Mac too?
Yes. Sign in with the same Apple ID on your iPad or Mac, go to Messages settings, and turn on iMessage. Your messages will sync across all your devices. You can send and receive iMessages from any of them.
Why do my iMessages sometimes show as green instead of blue?
iMessage automatically switches to regular text (green) when you message someone without an Apple device, or when iMessage delivery fails for technical reasons. This is normal and happens without you doing anything.
Does iMessage cost money?
No. iMessage uses your WiFi or cellular data plan, not your text message plan. If you have unlimited data, iMessage costs nothing. If you have a limited data plan, iMessages count toward that limit, but they typically use very little data.
What if someone blocked me — will I see blue or green messages?
If someone blocks you, your messages will usually show as green (regular text) because iMessage delivery will fail. You won't receive a notification that you're blocked, but the color change is often a sign.
Can I turn off read receipts for just one person?
No. Read receipts are all-or-nothing in iMessage settings. Go to Settings > Messages and toggle "Send Read Receipts" on or off for everyone at once. However, you can turn off notifications for specific conversations by swiping left on the conversation and tapping the bell icon.