The short answer
- A SIM swap moves your number to a SIM controlled by a scammer.
- A port-out scam transfers your number to another carrier.
- Sudden loss of calls, texts and mobile service can be a warning sign.
- Contact the carrier immediately, then secure email, financial and other important accounts.
Best preventionCarrier PIN / port lock
Safer loginPasskey or authenticator
Warning signUnexpected no service
First callYour carrier
How the scam works
A criminal gathers enough information to impersonate a mobile customer, then convinces or tricks the carrier into moving the number. Once the victim's phone loses service, the criminal may use the number to reset passwords or receive SMS verification codes. Port-out fraud uses a similar goal but transfers the number to another provider.
Warning signs
- Your phone unexpectedly shows no service while other nearby phones work.
- You receive a carrier notice about a SIM change, eSIM activation or number transfer you did not request.
- Password-reset messages or account-change alerts appear unexpectedly.
- You lose access to accounts that use the phone number for recovery.
Protection checklist
- Add a carrier-account PIN or passcode. Do not reuse a banking or email PIN.
- Ask about number lock or port-out protection. Carrier names differ, so confirm what is available.
- Use stronger authentication. Prefer passkeys, security keys or authenticator apps for important accounts when supported.
- Protect the email account first. Email often controls password resets for many other services.
- Limit public personal information. Birth dates, addresses and security-answer details can help impersonation attempts.
- Turn on carrier and account alerts. Treat unexpected changes as urgent.
Text-message 2FA is better than no 2FA, but it is not the strongest option
Move high-value accounts to phishing-resistant or app-based authentication where practical, while keeping tested recovery methods.
If your number is hijacked
- Contact the carrier immediately from another phone and ask it to restore control and investigate the change.
- Secure your primary email and change important account passwords.
- Review banks, cards, payment apps and crypto accounts for unauthorised changes.
- Replace compromised SMS recovery with stronger authentication.
- Save carrier notices and account alerts, and report fraud through the relevant local authority.