Guides / SIM swap

SIM swap: the signs and what to do

Updated 4 November 2026 · By the FirstHour team

Short answerA SIM swap is when someone gets your phone number moved onto a SIM they control, so your calls and texts, including login codes, reach them. One sign official sources list is your phone suddenly losing service. If that happens, contact your network from another phone right away, then change the passwords for your bank and email. You can make it harder to happen, and none of it needs panic.

What a SIM swap is

Your phone number is tied to a SIM or eSIM. In a SIM swap, a criminal asks your network to move your number to a SIM or eSIM they control. Verizon (a US network) describes it as a customer's number being "transferred to a different SIM card or eSIM profile under the control of a criminal". Police Scotland (UK) says criminals use personal data from leaks or phishing to pass the network's security checks.

It matters because many accounts send a code by text to prove it's you. The UK's National Cyber Security Centre says attackers carry out SIM swaps to get at codes sent by text. This is not the same as a stolen phone. Your phone can be in your hand and the number can still be taken.

The signs

Canada's Cyber Centre adds that a successful swap means you lose cellular service and Wi-Fi calling. Verizon says your phone suddenly stopping may be the first sign. A dropped signal is often just a bad signal, so treat it as a reason to check, not proof.

What to do right away

  1. Contact your network from another phone. The FTC says to contact your provider immediately to take back control of your number. Use the contact details on the network's own website or app, or ask the person you borrow the phone from to help. Who to call depends on your country, so pick yours here.
  2. Then your bank and email. Verizon advises changing the passwords for your financial and email accounts right away. The FTC says to check your credit card, bank and other financial accounts for charges or changes you didn't make. Our reasoning for email: it is often how other accounts are reset. Protecting your email has the steps, and your bank has its own guide.
  3. Which comes first? The FTC says to contact your provider first and change your account passwords once you have your number back. Verizon says to change the financial and email passwords right away. Our advice: contact your network first if you can, and if you can't reach it quickly, call your bank anyway rather than wait.
  4. Report it. Police Scotland says you can report a SIM swap to it online, by phone or in person. Other countries have their own police or fraud reporting.
  5. Don't give out a code. Police Scotland warns that if someone claiming to be your provider asks for your code, you should not give it to them.

If your phone was stolen rather than swapped, start with what to do if your iPhone is stolen and getting a replacement SIM.

How to make it harder

A SIM PIN on your iPhone is still worth setting, because it stops your SIM being used in another phone. This is our advice, not something the sources say: a swap is asked for at your network, not on your phone, so a SIM PIN on its own may not stop one. The network-side protection above is the part aimed at it.

How FirstHour helps

Plan B has a guided tip for setting a SIM PIN, lets you tick your network so its number is ready in your first-hour plan (checked numbers are built in for the Philippines and the US so far), and keeps your phone's details. It cannot detect a SIM swap or stop one. Your network does that, and FirstHour can't contact it for you.

Questions

Is losing signal always a SIM swap?

No. Poor coverage, a network fault or a phone problem can look the same. Check from another phone or ask your network. If you are unsure, it costs little to ask.

Sources

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