How to set a carrier PIN to prevent SIM swap attacks

Why this matters

A SIM swap is when an attacker convinces your mobile carrier to transfer your phone number to a SIM card they control. The moment they succeed, your phone loses service and the attacker starts receiving your calls and texts — including SMS 2FA codes for your email, bank, and crypto accounts. From there, account takeovers cascade in minutes.

The defense is a PIN or passcode that the carrier must hear before making any changes to your account. It’s free, takes one phone call, and shuts down the attack at the source. SIM swap losses topped a billion dollars in 2024 alone — this is not a hypothetical risk.

How to do it

1. Find your carrier’s customer support number (usually on a bill or the carrier’s app).
2. Call them and say: “I want to set up a customer service PIN — also called a port-out PIN or account PIN — to prevent SIM swap fraud.”
3. They’ll walk you through setting a 4- to 8-digit PIN. Choose one different from your normal PINs and birthdays. Save it in your password manager.
4. Ask them to also add a note that account changes require in-person verification at a store or an extra security question. Major US carriers offer this:
   • Verizon: Number Lock + Account PIN
   • AT&T: Wireless Passcode + extra security
   • T-Mobile: Account PIN + Port-Out Protection in the app
5. Repeat this for any household member whose phone number is used for shared family accounts or as a 2FA fallback.

What you don’t need

You don’t need to delete your phone number from every account — that’s overkill for most people, and some accounts require a phone number for legitimate reasons. The carrier PIN closes the actual vulnerability without uprooting your life. You also don’t need to switch carriers; all major carriers support this.