No SIM, Invalid SIM, or SIM Not Supported means the iPhone cannot use the cellular card or plan it expects. The cause is often a SIM that is not seated correctly, a damaged card, outdated carrier settings, or a carrier activation problem.
These steps apply mainly to iPhones with a physical SIM tray. Most US iPhone 14 and later models use eSIM only and need the eSIM checks below instead.
Does This Affect You?
Use this if your iPhone loses carrier service and shows a SIM warning even though a SIM is inserted. Start by reseating the card because it fixes many cases quickly.
Reseat the SIM Card
- Power off the iPhone.
- Find the SIM tray and press a SIM eject tool or straightened paperclip into the pinhole.
- Remove the tray and take out the SIM.
- Check the card for bends, chips, dirt, or damaged gold contacts.
- Wipe the gold contacts gently with a dry lint-free cloth.
- Place the SIM flat in the tray with the notched corner aligned.
- Push the tray in until it sits flush, then turn the iPhone back on.
If the tray feels loose or the card is bent, the physical fit may be the whole problem.
Update Carrier Settings and Restart
- Connect to Wi-Fi.
- Open Settings > General > About.
- If a carrier settings update appears, tap Update.
- Turn Airplane Mode on, wait 15 seconds, and turn it off.
- Restart the iPhone.
- If you can borrow another compatible SIM, test it in your iPhone.
Rule Out Card, Tray, or Account Problems
- Try your SIM in another phone if possible. If it fails there too, ask the carrier for a replacement SIM.
- Inspect the SIM tray for bends or damage. It should sit flush when inserted.
- Think about recent drops, liquid exposure, or impacts near the SIM side of the phone.
- Contact the carrier to confirm the SIM is active, provisioned, and assigned to your account.
What the Error Can Mean
No SIM
No SIM usually means the iPhone is not detecting a card at all, often due to seating, tray, card, or hardware contact problems.
Invalid SIM or SIM Not Supported
These messages can point to a carrier-side issue, inactive SIM, SIM from the wrong account, or a carrier-locked iPhone being used with another provider.
eSIM-Only iPhones
If your iPhone has no physical tray, open Settings > Cellular and confirm the eSIM plan is listed and enabled. Contact the carrier if the plan is missing.
Network Reset
If the SIM and account are fine, reset network settings to clear corrupted cellular configuration. You will need to rejoin Wi-Fi afterward.
Sources
- Apple Support: If your iPhone or iPad does not recognize your SIM card
- Apple Support: Use a SIM card with your iPhone
- Apple Support: About eSIM and cellular service on iPhone