SMS is already on your iPhone — you just need to check one setting
SMS (Short Message Service) is the technical name for text messages. Your iPhone can send and receive them, but the feature lives inside the Messages app and sometimes needs to be turned on in Settings. If you can't send texts or they're not arriving, the fix is usually a single toggle in your phone's settings, not a separate read or account.
The reason SMS sometimes appears "off" is that Apple groups it with other messaging options — iMessage (which uses data instead of your phone plan), MMS (picture messages), and group messaging. Each can be controlled separately. Most people never need to touch these settings, but if texts aren't working, one of them is usually the culprit.
Key Takeaways
- SMS is text messaging through your phone plan, and it's controlled in Settings under Messages, not in the Messages app itself.
- If you can't send texts, check that "Send as SMS" is turned on in Settings — Messages — SMS/MMS.
- If texts aren't arriving, make sure "Filter Unknown Senders" is off unless you want to hide messages from people not in your contacts.
- Turning off iMessage temporarily can help you figure out whether a texting problem is with SMS or with Apple's data-based messaging.
Check if SMS is turned on in Settings
Open Settings on your iPhone and scroll down to find Messages. Tap it. You'll see several toggles. The one you need is called "Send as SMS" — make sure it's green (on). This setting tells your phone to send a regular text message if iMessage fails or if the person you're texting doesn't have an Apple device.
If "Send as SMS" is already on and you still can't send texts, scroll down in the same Messages settings screen and look for "MMS Messaging." This controls picture and group messages. Turn it on if it's off. Both of these settings require an active phone plan with texting included — if your plan doesn't have texting, no setting will fix that.
Turn off iMessage if texts aren't working
iMessage is Apple's messaging system that works over data or WiFi instead of SMS. When iMessage is on, your iPhone tries to send messages through iMessage first, then falls back to SMS if that fails. Sometimes iMessage gets stuck and blocks SMS from working at all.
To test this, go back to Settings — Messages and turn off "iMessage" (the first toggle at the top). Wait 30 seconds, then try sending a text to someone. If the text goes through now, iMessage was the problem. You can turn iMessage back on after that — the issue usually fixes itself once you've restarted the connection. If texts still don't work with iMessage off, the problem is with your phone plan or carrier, not your iPhone's settings.
Stop hiding texts from unknown numbers
If you're receiving texts from people in your contacts but missing texts from new numbers, check the "Filter Unknown Senders" toggle in Settings — Messages. When this is on, texts from people not in your phone's contacts go to a separate tab called "Unknown Senders" instead of your main message list. They're still arriving — you just have to look in a different place.
Turn this off if you want all texts to land in your main inbox. Turn it on if you want to reduce clutter and only see messages from people you know. Either way, the texts are there — this setting just controls where they show up.
Make sure your carrier supports SMS
SMS requires an active phone plan with texting included. If you're using an iPhone on a plan that doesn't include texts, or if you're on WiFi-only (like an old iPad), SMS won't work no matter what settings you change. Check with your carrier — the company that provides your phone service — to confirm your plan includes texting.
If you're traveling internationally, texting might be blocked or charged at a different rate. Contact your carrier before you travel, or turn on Airplane Mode and use WiFi-only messaging (iMessage or apps like WhatsApp) to avoid surprise charges.
Restart your iPhone if texts still aren't working
If you've checked all the settings above and texts still aren't sending or arriving, restart your phone. Press and hold the power button (on the side of the phone) until you see "slide to power off." Slide to turn it off, wait 10 seconds, then press the power button again to turn it back on. This clears out temporary glitches that sometimes block texting.
After the restart, try sending a text again. If it still doesn't work, contact your carrier's customer support — the problem is likely with your phone plan or account, not your iPhone.
Frequently Asked Questions
What's the difference between SMS and iMessage?
SMS is text messaging through your phone plan — it costs money only if your plan doesn't include unlimited texts. iMessage is Apple's system that sends messages over data or WiFi and doesn't use your text allowance. iMessage only works between Apple devices; SMS works with any phone.
Why do some of my texts show as blue and others as green?
Blue means the message was sent through iMessage (to another Apple device). Green means it was sent as SMS (through your phone plan). If a text to an iPhone friend shows green, it means iMessage failed and your phone fell back to SMS.
Can I send texts over WiFi without a phone plan?
Only through iMessage or apps like WhatsApp. Regular SMS requires an active phone plan with texting. If you have WiFi but no phone plan, turn on iMessage and you can text other Apple users without SMS.
Why are my texts going to the Unknown Senders tab?
You have "Filter Unknown Senders" turned on in Settings — Messages. This sends texts from people not in your contacts to a separate tab. Go to Settings — Messages and turn off this toggle if you want all texts in your main inbox.
Do I need to do anything to receive texts, or is it automatic?
It's automatic. As long as SMS is turned on in Settings and you have an active phone plan, your iPhone receives texts without any action from you. If texts aren't arriving, check that "Send as SMS" is on and that you're not accidentally filtering them to Unknown Senders.