What Is a SIM Swap Scam, and How Can You Prevent It?

Your phone number feels like a small thing. It is not. These days, a phone number is often the key that lets you reset a password or prove it is really you logging in.

That is exactly why criminals want it. A SIM swap scam lets someone take over your phone number without ever touching your phone.

This guide explains what a SIM swap scam is, the warning signs to watch for, and the one simple step, a PIN or passcode with your carrier, that goes a long way toward stopping it.

What Is a SIM Swap Scam?

A SIM swap scam is when a criminal convinces your phone carrier to move your phone number onto a SIM card they control, so your calls and texts go to them instead of you.

Here is how it usually plays out. A criminal first gathers personal details about you, sometimes from a data breach, a social media post, or a phishing text. They use that information to call or message your carrier, pretending to be you. They claim your phone was lost, stolen, or damaged, and ask for your number to be activated on a new SIM card, one they hold.

If the carrier’s staff is convinced, your number moves. Your real phone goes silent. The criminal’s phone now receives everything meant for you, including the text message codes banks and email providers use to confirm it is really you signing in.

From there, they can reset your passwords, get into your email, and move money out of your bank accounts, all using codes that were supposed to keep you safe.

Why Criminals Want Your Phone Number

Many banks, email providers, and social media sites use your phone number as a backup way to confirm your identity. This is often called two-factor authentication, or 2FA for short.

Two-factor codes sent by text are far better than no protection at all. But if a criminal has swapped your SIM, those codes go straight to them, not you. That turns a safety feature into an open door.

According to the FBI’s Internet Crime Complaint Center, SIM swap complaints and losses have grown sharply in recent years, with more than 1,600 complaints and over $68 million in reported losses in a single year. This is not a rare, unlucky event. It is a well-organized type of fraud.

Warning Signs of a SIM Swap Scam

The good news is that a SIM swap usually leaves clear clues, if you know what to watch for.

According to the FTC, one of the clearest signs is your phone suddenly showing “no service,” with no calls, texts, or data, even in a place where you normally get good reception.

How Can You Prevent a SIM Swap Scam?

The single most effective step is calling your carrier and adding a PIN or passcode to your account, one that must be given before anyone can move your number to a new SIM or a different carrier.

Most major carriers offer this, though they may call it slightly different things, such as an account PIN, a porting PIN, or a passcode. Here is how to set it up.

1. Call your carrier’s customer service number, the one printed on your bill or on the back of your SIM card.
2. Tell them you want to add a PIN, passcode, or “port protection” to your account to prevent unauthorized SIM changes.
3. Choose a PIN that is not your birth year, your address number, or anything else easy to guess.
4. Ask the representative to confirm, out loud, that this PIN will now be required before any SIM change or number transfer.
5. Write the PIN down somewhere safe, not on a sticky note on your computer, and keep it separate from your other passwords.

A few more habits help too:

• Avoid posting your full phone number, birth date, or address on social media, since criminals use these details to sound convincing to carrier staff.
• Use an authenticator app instead of text messages for two-factor authentication on your email and banking accounts, when the option is offered.
• Be cautious about unexpected texts or calls asking you to “verify” your account or confirm a code. Never read a code out loud to someone who called you.
• If you get a “welcome” text for a new phone or plan you did not set up, treat it as an emergency and call your carrier immediately.

The FCC adopted new rules in November 2023 requiring wireless carriers to use secure methods to verify your identity before moving your number to a new SIM or carrier, and to notify you whenever such a change is requested. That is a helpful step, but adding your own PIN with your carrier now is still the fastest way to protect yourself.

What to Do if You Think You Have Been SIM Swapped

Move quickly if you notice the warning signs above.

1. Call your carrier from a different phone and ask them to secure your account and restore your number.
2. Log into your email and bank accounts from a device you trust, and change passwords for anything tied to your phone number.
3. Turn on an authenticator app for two-factor authentication where you can, instead of text codes.
4. Check your bank and credit card statements for anything unfamiliar, and report it.
5. Freeze your credit if you suspect a criminal now has enough information to open new accounts in your name. Our guide on how to freeze your credit after a scam walks through the steps.

If you are not sure what to click, close, or say next, our calm 10-minute checklist for after a scam is a good place to start. You can also find the right agency to contact in our guide on where to report a scam.

Criminals who use SIM swapping often use the same tricks over the phone, including impersonating a bank or even a family member. If that worries you, our guide to setting up a family safe word is a simple extra layer of protection worth adding.

Where to Go From Here

A SIM swap scam works because it exploits trust, between you and your carrier, and between your accounts and your phone number. A PIN with your carrier closes that gap in a few minutes on the phone.

If scams like this worry you, our scam-proof guide walks through this one and many others, in the same plain, step-by-step way, so you always know what to check and what to do next.