What to do if…
your phone suddenly shows No SIM and your number stops working

What to do now

1. Get a working connection so you can act.

   • Turn Wi-Fi on and connect to a trusted network.
   • Use an internet calling or messaging app you already have, or borrow someone’s phone to make calls.
   • Keep your affected phone with you, but do not keep retrying random fixes.

2. Do the fast, low-risk phone checks.

   • Toggle Flight mode on and off once.
   • Restart the phone.
   • Check that your mobile plan still appears active in your provider’s official app or account page, if you can access it safely over Wi-Fi.
   • If you have a physical SIM: power off, remove the SIM, check for obvious damage or dirt, reseat it carefully, and restart.
   • Check for a network provider settings, network, or system update and install it if your phone prompts you.

3. Test whether it is the SIM, the phone, or the account.

   • If possible, put your SIM in a compatible spare phone, or try a known-working SIM in your phone.
   • If your SIM fails in more than one phone, treat it as a SIM or account-level problem until your provider confirms otherwise.
   • If a known-working SIM also fails in your phone, tell your provider that the handset or SIM tray may also need checking.

4. Contact your mobile provider immediately from another phone.

   • Use a number from your bill, the provider’s official app, or their official website.
   • Say: “My phone shows ‘No SIM’ and my number stopped working. Please check whether a SIM swap, eSIM reissue, replacement SIM, or number port has happened on my account today.”
   • Ask them to block or reverse any unauthorised SIM or porting change if they find one.
   • Ask what account protections they can apply now, such as an account PIN, extra verification, or a note that the account is at risk of SIM-swap fraud.
   • Ask them to confirm the next safe step before you change, delete, or reinstall any eSIM profile.

5. If there is any chance of takeover, secure the accounts that matter most.

   • Email first: change the password, sign out of other sessions or devices, and check recovery phone numbers and email addresses.
   • Banking and finance next: use the bank’s official app or website over Wi-Fi, or call the number on your card; ask them to watch for unauthorised activity.
   • Apple ID or Google account next: change the password and review trusted devices, recovery details, and recent sign-ins.
   • Where the account allows it, switch away from SMS codes to an authenticator app, passkeys, or another stronger sign-in method.

6. Capture useful evidence before it disappears.

   • Screenshot the “No SIM” or “Invalid SIM” message with the date and time visible if possible.
   • Save any provider emails, app notifications, or texts about SIM changes, eSIM changes, replacement SIMs, PAC codes, STAC codes, or number ports.
   • Write down when service stopped and what your provider tells you.

7. If you believe it is fraud, report it after the provider and key accounts are secured.

   • In England, Wales, or Northern Ireland, report fraud or cyber crime to Report Fraud.
   • In Scotland, report to Police Scotland via 101 for non-emergencies, or 999 if someone is in immediate danger or a crime is in progress.
   • If you clicked a suspicious link, handed over details, or received scam texts or emails, use the GOV.UK suspicious message reporting route as well.