Apple sends text messages only through iMessage, and only to other Apple devices

Apple does not run a traditional text messaging service. Instead, Apple devices use iMessage, which is Apple's encrypted messaging system built into iPhone, iPad, Mac, and Apple Watch. iMessage messages travel over data (WiFi or cellular data) rather than through your phone carrier's SMS network. If you send a message to another Apple user and both devices are connected to the internet, the message goes through iMessage and appears in a blue bubble on your screen.

If you send a text to someone with an Android phone or another non-Apple device, your iPhone automatically falls back to regular SMS (text message) sent through your carrier. That message appears in a green bubble. Apple is not sending it — your carrier is. You pay for it the same way you pay for any other text message, either through your plan's text allowance or per-message charges if you have an older plan.

The confusion often comes from the fact that you do not choose which system to use. Your iPhone decides automatically based on whether the recipient's device supports iMessage. You cannot force an iMessage to go to an Android phone, and you cannot force an SMS to go to an iPhone user if iMessage is available.

Key Takeaways

  • iMessage is Apple's messaging system for Apple devices only, and it uses your data connection rather than SMS.
  • When you text an Android user from an iPhone, your carrier sends a regular text message, not Apple.
  • Your iPhone automatically chooses between iMessage (blue bubbles) and SMS (green bubbles) based on the recipient's device.
  • iMessage messages are encrypted end-to-end, while SMS messages sent through your carrier are not.
  • You do not receive bills from Apple for iMessage, but you may have SMS charges from your carrier depending on your plan.

How to tell whether a message went through iMessage or SMS

Open the conversation in the Messages app on your iPhone. Look at the color of the message bubble. If the bubble is blue, the message used iMessage. If it is green, the message was sent as SMS through your carrier. The color tells you which system carried that particular message.

You can also look at the "Delivered" status. iMessage shows "Delivered" and "Read" receipts if the recipient has read receipts turned on. SMS messages show only "Delivered" status, and only if your carrier supports delivery reports — many do not. If you see no status at all, the message likely went through SMS and your carrier does not report delivery.

At the top of the conversation, you may see the recipient's name followed by their phone number or email address. If it shows an email address, that message went through iMessage. If it shows only a phone number, it went through SMS.

Why your messages might be green instead of blue

The most common reason is that you are texting someone with an Android phone or another non-Apple device. iMessage only works between Apple devices, so your iPhone has no choice but to send SMS instead.

Sometimes an iPhone user's iMessage is turned off. If someone has disabled iMessage in their Settings, your messages to them will be green even though they own an Apple device. You can ask them to turn iMessage back on in Settings > Messages > iMessage.

Poor internet connection can also cause this. iMessage requires an active data connection. If your iPhone cannot reach the internet, it will fall back to SMS automatically. Once your connection improves, new messages to that person may go blue again.

If a contact recently switched from iPhone to Android, your iPhone may not have updated their device status yet. It can take a few hours or even a day for Apple's servers to recognize that the person no longer has an Apple device. During that time, your messages may still try to go through iMessage and fail, then fall back to SMS.

What iMessage costs and what SMS costs

iMessage itself costs nothing. Apple does not charge you for iMessage messages. You use your existing data plan — the same data you use for email, web browsing, and apps. If you have unlimited data, iMessage is truly free. If you have a limited data plan, iMessage uses a small amount of that data, but the amount is negligible for text messages.

SMS messages cost whatever your carrier charges. Many modern plans include unlimited text messages, so you pay nothing per message. Some older plans charge per text message, typically 20 cents or more per message. A few plans have a limited number of texts per month and charge overage fees after that. Check your carrier's plan details to know what you are paying for SMS.

The key difference: if you are texting someone with an iPhone and iMessage works, you are using data and paying nothing extra. If you are texting someone with an Android phone, you are using SMS and paying whatever your carrier charges for texts.

How to turn iMessage on or off

On iPhone, open Settings, then tap Messages. Toggle iMessage on or off. If you turn it off, all your text messages will go through SMS, even to other Apple users. This means they will appear in green bubbles and you will use your carrier's text message allowance instead of data.

On iPad or Mac, the process is similar. Open Settings (iPad) or System Settings (Mac), find Messages, and toggle iMessage on or off. If you have multiple Apple devices, you can turn iMessage on for some and off for others, though Apple recommends keeping it on across all your devices so you do not miss messages.

If you are switching from iPhone to Android, Apple recommends turning off iMessage on your old iPhone before you stop using it. If you do not, messages from iPhone users may still try to go through iMessage and fail to reach you. You can turn it off in Settings > Messages > iMessage, or you can use Apple's deregister iMessage tool on Apple's website if you no longer have access to the phone.

Privacy and security differences between iMessage and SMS

iMessage messages are encrypted end-to-end, which means Apple's servers cannot read them. Only you and the recipient can read the message content. SMS messages sent through your carrier are not encrypted in the same way. Your carrier can see the message content, and so can anyone else who intercepts the message on the network.

This does not mean SMS is unsafe for everyday use. Carriers have legal obligations to protect your data, and intercepting text messages requires technical skill and access to network infrastructure. But if you are sending sensitive information — passwords, financial details, or private conversations — iMessage is more secure because the encryption is stronger and Apple cannot access the content.

Both iMessage and SMS can be read by someone who has physical access to your phone or who has compromised your Apple ID. The encryption protects the message in transit, not on your device itself.

What to do if iMessage is not working

First, check that iMessage is turned on. Go to Settings > Messages and make sure the iMessage toggle is green. If it is off, turn it on and wait a few seconds for it to activate.

Next, check your internet connection. iMessage requires WiFi or cellular data. If you are on airplane mode or have no signal, iMessage will not work. Turn off airplane mode or move to a location with better signal.

If iMessage is on and you have internet, try signing out and back in to your Apple ID. Go to Settings > Messages > Send & Receive, tap your Apple ID at the top, and select Sign Out. Wait a few seconds, then sign back in with your Apple ID password.

If the problem persists, restart your iPhone. Hold the power button until "Slide to Power Off" appears, slide to turn it off, wait 10 seconds, then press the power button again to turn it back on. After the restart, try sending an iMessage again.

If you still cannot send iMessage to a specific person, ask them whether iMessage is turned on on their device. If they have an Android phone or iMessage is off, your messages will be green SMS instead, and that is normal.

Frequently Asked Questions

Can Apple see my iMessage messages?

No. iMessage messages are encrypted end-to-end, which means Apple's servers process the message but cannot read its content. Only you and the recipient can read what you wrote. Apple can see that a message was sent and received, but not what the message says.

Do I get charged for iMessage if I am on a limited data plan?

iMessage uses a tiny amount of data per message — typically less than 1 kilobyte. On a limited data plan, you will use some of your monthly allowance, but the amount is so small that it is not worth worrying about. You would have to send thousands of iMessages to notice any impact on your data usage.

Why do my messages to my friend keep turning green after being blue?

This usually means their iMessage is turning on and off, or they are switching between devices. If they use both iPhone and Android, messages may be blue when they are on iPhone and green when they are on Android. You can ask them to check whether iMessage is consistently on in their Settings.

If I turn off iMessage, will I still receive messages from iPhone users?

Yes. If you turn off iMessage on your iPhone, iPhone users can still text you, but their messages will come through as SMS instead of iMessage. You will receive them normally, but they will appear in green bubbles and may count against your carrier's text message limits if you have a limited plan.

What happens to my iMessage conversations if I switch to Android?

Your iMessage conversation history will remain on your iPhone, but you will not be able to access it on Android. Before you switch, you can take screenshots of important conversations or use a backup service. After you switch, turn off iMessage on your old iPhone so that iPhone users' messages reach you on your Android phone as SMS instead.