# How do I know if I’ve been SIM swapped?

> **Short answer:** The clearest sign is that your phone suddenly loses service where coverage is normally fine, and calls and texts stop arriving. Other signs are a carrier notice about a SIM change or number transfer you didn’t request, and password-reset or new-login alerts from accounts you didn’t touch. Contact your carrier from another phone immediately.

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## Signs to look for

- **Sudden loss of service:** no bars, no calls and no texts where your phone normally works. Your SIM stops working when the number is moved to someone else’s.
- **A carrier notice you didn’t expect:** a message or email about a SIM change, a new eSIM, or a request to transfer your number to another carrier.
- **Security alerts from other accounts:** password-reset emails, “new sign-in” notices or one-time passcodes you didn’t request.

## Why carrier notices are the early warning

The FCC’s 2023 rules require US wireless carriers to notify customers promptly when a SIM change or port-out is requested on their account.[^1] That notice may be the first thing you see, so read carrier messages about account changes rather than dismissing them.

## What to do first

Call your carrier from another phone to stop the transfer and recover your number, then secure your email account, because that is where password resets for everything else land. In the US, the FTC’s IdentityTheft.gov builds a recovery plan and report.[^2] Step by step: [respond to a SIM swap](https://glide-cleartext.pages.dev/checklists/respond-to-a-sim-swap/).

## What this means for you

### Banks & credit unions

A customer reporting a sudden loss of phone service may be describing a SIM swap in progress. Route those calls to fraud, not general support, and review recent logins, payee additions and contact-detail changes.

### Fintechs & payment firms

Give users a fast way to freeze their account from a second device or by email. The first minutes after a SIM swap are when funds move.

### Developers & identity teams

Send security alerts to more than one channel. If the only alert for a password reset goes by SMS, a SIM-swapped user never sees it.

## Follow-up questions

**Can a SIM swap happen without me noticing?**

Rarely for long. When the number moves, your own SIM stops working on the network, so loss of service is usually visible within minutes.

**Where do I report it in the US?**

Your carrier first, to recover the number. Then your bank and the affected services, and the FTC at IdentityTheft.gov, which produces a recovery plan.


## Sources

[^1]: Protecting Consumers from SIM Swap and Port-Out Fraud. Federal Register, 2023-12-08. https://www.federalregister.gov/documents/2023/12/08/2023-26338/protecting-consumers-from-sim-swap-and-port-out-fraud
[^2]: IdentityTheft.gov. US Federal Trade Commission. https://www.identitytheft.gov/

## Related questions

- [What is a SIM swap attack?](https://glide-cleartext.pages.dev/q/what-is-a-sim-swap-attack/)
- [What does the FCC SIM swap rule require?](https://glide-cleartext.pages.dev/q/what-does-the-fcc-sim-swap-rule-require/)
- [How can banks defend against SIM swap fraud?](https://glide-cleartext.pages.dev/q/how-can-banks-defend-against-sim-swap-fraud/)

## Cite

Cleartext. “How do I know if I’ve been SIM swapped?” Last verified 2026-09-10 (rev. 1). https://glide-cleartext.pages.dev/q/how-do-i-know-if-i-have-been-sim-swapped/

## Changelog

- 2026-09-10: First published.