What is SIM swap fraud?
SIM swap fraud is when a criminal convinces your mobile network to move your number onto a SIM card they control, without you ever agreeing to it. The moment it works, your phone loses signal, and your texts, including the one time codes banks and email providers send to “verify it’s you”, start landing in someone else’s hands instead.
It’s a quiet crime. There’s no phone call demanding money, no dodgy link to click. Your phone just stops working, and by the time you notice, the damage is often already underway.
How do criminals pull off a SIM swap?
Most SIM swap fraud starts with information, not hacking in the Hollywood sense. Criminals gather enough personal detail, sometimes from a data breach, sometimes from social media, sometimes just guessed, to convince your network they’re you. Then they ask for the number to be moved to a new SIM.
Increasingly, that request happens entirely online rather than in a shop or over the phone, which makes the identity checks harder to get right. Once your number’s on their SIM, they can reset passwords on your email, banking and social accounts using SMS codes sent straight to them.
How fast is SIM swap fraud growing in the UK?
SIM swap fraud isn’t a fringe problem any more. Fraud prevention service Cifas recorded a sharp rise in reported cases in 2025 compared with the year before, and consumer group Which? has publicly pushed mobile networks to tighten their checks.
SIM swap fraud at a glance, checked August 2026
| What’s changed | Detail |
| Reported cases | Cifas recorded a sharp year on year rise in 2025 |
| Where swaps happen | Increasingly online, not in store or by phone |
| Main target | SMS codes used to reset banking, email and social accounts |
| Regulator pressure | Which? has called on networks to strengthen ID checks |
How can you protect your number from SIM swap fraud?
Start with your network account. Most UK networks let you set a port out PIN or a “number lock” that has to be entered before your number can be moved anywhere. Turn it on, then forget about it until you actually need it.
Next, look at what SIM swap fraud is actually trying to steal, your SMS codes, and take that route away. Where you can, swap text message two factor authentication for an authenticator app or a passkey instead. It’s not always possible, but for the accounts that matter most, email and banking, it’s worth the ten minutes it takes to set up.
A strong, unique password on your mobile account itself matters too. If a criminal can’t log in to request changes in the first place, SIM swap fraud gets a lot harder to pull off.
Who do criminals actually target?
Anyone with a mobile number can be a target, but SIM swap fraud tends to follow the money. Criminals often go after people whose social media gives away crumbs of personal information, a mother’s maiden name in an old photo caption, a pet’s name used as a password hint, a phone number listed publicly for a small business.
Crypto holders and anyone with a large, guessable online footprint tend to be targeted more often too, since the payoff for a successful SIM swap can be much bigger than an ordinary bank account. That said, ordinary households get caught out as well. The checks a criminal needs to pass often aren’t that demanding.
What should you do if you think you’re a victim?
Sudden loss of signal for no obvious reason is the classic warning sign, especially alongside a “SIM activated” text you didn’t request. Call your network immediately from another phone and ask them to block the swap and restore your number.
After that, change your email and banking passwords straight away, from a device that’s still definitely yours, and check recent account activity for anything you don’t recognise. Report it to Action Fraud and to your bank if any money has moved.
Key takeaways
- SIM swap fraud moves your number to a criminal’s SIM so they intercept your calls and texts.
- Reported cases rose sharply in 2025, and most swaps now happen online.
- Set a port out PIN or number lock with your network today, it takes minutes.
- Prefer an authenticator app or passkey over SMS codes for your most important accounts.
- Sudden loss of signal plus an unexpected “SIM activated” text means act immediately.
If you’re shopping for a new phone or network anyway, our guide on multi network SIMs covers a different way to avoid losing signal altogether, and checking a phone’s IMEI is worth a read if you’re buying second hand. For wider advice on protecting yourself, Action Fraud has current guidance.
Frequently asked questions about SIM swap fraud
- Can SIM swap fraud happen with an eSIM?
- Yes. An eSIM can be reassigned in a similar way to a physical SIM, so the same protections, a port out PIN and strong account password, still apply.
- Will my network refund losses caused by SIM swap fraud?
- It depends on the circumstances and whether the network followed its own security checks. Report it quickly and raise a formal complaint if you think checks were skipped.
- Does a screen lock on my phone stop SIM swap fraud?
- Not directly. SIM swap fraud targets your network account, not your handset, so a port out PIN matters more than your phone’s own lock screen here.
- How do I set a port out PIN?
- Check your network’s app or account settings, or call customer service and ask for a number lock or port out PIN to be added.
- Should I worry about SIM swap fraud if I’m not a high value target?
- It’s still worth the ten minutes it takes to set a port=out PIN. SIM swap fraud doesn’t only chase large accounts, and prevention is far less hassle than recovery.
