How do I protect my phone number from a SIM swap scam?

A friend lost access to her bank account after someone moved her phone number to their own SIM and got all her verification texts. I use text-message codes for almost everything. How do SIM swap scams work, and what can I do to protect my phone number?

Concerns & risks

You rely on SMS codes, a friend was hit by a SIM swap, and you want to lock down your number.

At a glance: warning signs
Sign	Action
Phone suddenly shows no service	Call carrier from another phone
Unexpected SIM change alert	Contact carrier now
Password reset emails you didn't ask for	Secure your email
Locked out of accounts	Use account recovery and report

Apple illustration of an iPhone with eSIM signal (Apple official image), annotated: Lock your number with your carrier — Lock your number with your carrier. Image: Apple (official source, cropped and annotated by ReportSpeed)

Overview diagram: Stop a SIM swap — Set carrier PIN; Lock your number; Use an authenticator; Act on no-service — The whole fix at a glance: set carrier pin, lock your number, use an authenticator, act on no-service. Original diagram by ReportSpeed

Causes & evidence

In a SIM swap, a scammer convinces or tricks a mobile carrier into moving your number to a SIM or eSIM they control, often using personal details gathered from data breaches or social media. Once they have your number, they can receive your calls and texts, including one-time passcodes, and reset passwords. The FCC has adopted rules requiring wireless carriers to use secure methods to authenticate customers before SIM changes and number port-outs, and to notify customers when those requests happen. Many carriers also offer account PINs and a number lock or port-out protection setting.

Carriers name their protections differently: number lock, port-out protection or SIM protection. Check your carrier's account settings or call.

Troubleshooting flowchart: try each step in order and stop when it is fixed — How do I protect my phone number from a SIM swap scam — Work through it in order and stop when the problem is gone. Original diagram by ReportSpeed

Using SMS codes for your email and bank while your carrier account has no PIN leaves your most important accounts one phone call away from takeover.

What to do

Step illustration: numbered steps for How do I protect my phone number from a SIM swap scam — The steps from this answer as numbered cards. Original diagram by ReportSpeed

Comparison chart: SIM swap protection at a glance — SIM swap protection at a glance. Original diagram by ReportSpeed

SIM swap protection at a glance
Protection	What it does
Carrier account PIN	Required before account changes
Number lock / port-out protection	Blocks SIM changes or ports until you turn it off
Authenticator app or passkey	Codes that don't travel by text
Carrier alerts	FCC rules require notice of SIM change requests
Sudden 'no service'	Possible warning sign; contact carrier immediately

Log in to your carrier account and set a strong, unique account PIN.
Turn on number lock or port-out protection if your carrier offers it.
Switch your email, bank and other key accounts from SMS codes to an authenticator app or passkeys.
Limit personal details like your birthday and phone number on social media.
If your phone suddenly loses service unexpectedly, call your carrier from another phone right away.

Common mistakes:

Reusing your carrier PIN elsewhere
Keeping SMS as the only second factor on email
Ignoring a sudden loss of service

ReportSpeedMan tip: Your email account is the master key to most password resets, so protect it with the strongest second factor you can.

What I would actually do

I'd set a carrier PIN, turn on number lock and move my email and bank to an authenticator app the same day.

The trade-off people miss: number lock adds a step when you switch carriers or phones yourself. Remember how to turn it off.

Checking that it worked

Your carrier PIN and number lock are on and key accounts use an authenticator.

Quick FAQ

Does eSIM stop SIM swaps?
Not by itself.

Is SMS 2FA useless?
It's better than nothing, but apps are stronger.

What do I do if it happens?
Call your carrier, then secure email and bank.

Wrap-up: Lock your carrier account, move key accounts off SMS codes and act fast on unexpected no-service. Those steps stop most SIM swaps.

Wiki: Multi-Factor Authentication (MFA) and Identity Theft Recovery Steps.

How do I protect my phone number from a SIM swap scam: where the facts come from

Step-by-step photos

1. Before The problem
2. Why it happens The cause
3. The fix The fix
4. After The result

⚡ Speed Summary

Lock your carrier account, move key accounts off SMS codes and act fast on unexpected no-service.
Your email account is the master key to most password resets, so protect it with the strongest second factor you can.
Using SMS codes for your email and bank while your carrier account has no PIN leaves your most important accounts one phone call away from takeover.

How do I protect my phone number from a SIM swap scam?

Concerns & risks

Causes & evidence