Contact the carrier from a trusted channel
If your number suddenly stops working and you suspect an unauthorised SIM change, contact the carrier using a known support route. Ask them to confirm the status of the line and restore control of the mobile account before you rely on SMS again.
Secure primary email from another device
Email is often the reset path for many other services. From a device or session you still trust, change compromised credentials if necessary, review recovery methods and make sure the attacker cannot use the moved number to reset the mailbox.
Prioritise accounts that accept SMS recovery
Banking, social, cloud and identity accounts that send codes to the number deserve immediate review. Replace the stolen recovery path with an independent factor where the provider allows it, and save new backup codes somewhere off the phone.
Revoke sessions you do not recognise
Check recent sign-ins, trusted devices, forwarding rules and connected apps. End suspicious sessions and undo unexpected changes before assuming that regaining the phone number has removed every foothold.
Review financial activity and account notifications
Look for password-reset messages, payment alerts, new payees or changes to security settings during the period when the number was out of your control. Contact the relevant provider promptly if you find activity you did not authorise.
Warn contacts if messaging accounts were exposed
If an attacker may have used your number or linked messaging accounts, tell important contacts not to trust unusual requests for money, codes or sensitive information. This limits damage that can continue after the SIM itself is recovered.
Related consequence reports for “SIM-swapped phone number: immediate security and recovery steps”
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Continue in this topic
Find more distinct decisions and source-backed consequence reports in the Security & 2FA topic hub.
Official sources for “SIM-swapped phone number: immediate security and recovery steps”
- FTC — SIM swap scamsOfficial source ↗
- FTC — Use two-factor authenticationOfficial source ↗
- Google — PasskeysOfficial source ↗
- NIST — Digital Identity Guidelines: AuthenticationOfficial source ↗
- FTC — Before you upgrade your phoneOfficial source ↗
- WhatsApp Help — Account deactivationOfficial source ↗
- WhatsApp Help — Change phonesOfficial source ↗
- WhatsApp Help — PasskeysOfficial source ↗
- Microsoft Support — Sign out of OfficeOfficial source ↗