SIM swap fraud: my phone suddenly lost signal, what do I do?

SIM swap fraud: my phone suddenly lost signal, what do I do?

You're at home, where your phone always works, and suddenly it shows "No service" or "SOS only". Restarting doesn't help. Your partner's phone, on the same network, works fine. It might be an outage, but it might also be something more serious: someone may have convinced your mobile network to move your number onto a new SIM card in their hands. It's called SIM swap fraud, and the goal is to receive the security codes your bank sends you by text. If you suspect it, every minute counts.

How does a SIM swap work?

1. They gather your details first. Through phishing texts or emails, data breaches, social media or a phone call pretending to be your bank, they collect your name, date of birth, address, account details and sometimes your online banking login.
2. They impersonate you with your mobile network. By phone, online or in a shop, sometimes with fake ID, they say they've lost their phone and ask for a replacement SIM or eSIM for your number. In some cases they port your number to another network.
3. Your SIM goes dead. The moment the new SIM is activated, yours stops working. Calls and texts go to them.
4. They empty your accounts. With your password and the codes that now arrive on their phone, they log into your online banking, add themselves as a payee, raise limits and move money. They can also take over your email, WhatsApp and other accounts that use text codes.

What are the warning signs?

• Your phone loses service suddenly in a place where it always works, and doesn't come back after restarting.
• Other phones on the same network work normally nearby.
• You get a text or email from your network about a SIM change, an eSIM activation or a port-out you didn't ask for.
• You stop receiving calls and texts while data over Wi-Fi still works.
• Messages arrive from your bank (by email or in the app) about new devices, payees or logins you don't recognise.
• Days before, you received suspicious calls or texts asking for personal or banking details.

What do I do right now?

1. Ring your mobile network from another phone (a family member's, a landline or by Wi-Fi calling if available). Use the customer care number on its official website or on your bill. Ask directly: "Has a replacement SIM or eSIM been issued for my number, or has it been ported?" If so, ask them to block it immediately and restore your line.
2. Ring your bank at the same time, on the number on the back of your card or on its official website. Explain that your number may have been hijacked and ask them to freeze online banking, block cards and check for recent payments and new payees.
3. Change your email password from a device you trust and sign out of all sessions. Your email is the key to resetting everything else.
4. Check your other accounts that use text codes: WhatsApp, social media, payment apps.
5. Keep evidence: the time you lost service, messages from your network and bank, screenshots.

What if money has already been taken?

• Tell your bank exactly what happened and ask for the unauthorised transactions to be investigated and refunded. Under EU payment rules, banks must refund unauthorised payments in many cases, unless they can show you acted fraudulently or with gross negligence; your bank will explain how this applies to your case.
• Report it to the Gardaí at your local Garda station, bringing the evidence and the confirmation from your network that a SIM was issued without your consent. Online fraud is supported by the Garda National Cyber Crime Bureau.
• Complain to your mobile network in writing, asking how the SIM was issued and what checks were made. If you're not satisfied with its answer, you can take the complaint to ComReg, the communications regulator, once you've been through the network's own complaints process.
• If the bank refuses to refund you and you disagree, complain formally to the bank; then you can go to the Financial Services and Pensions Ombudsman (FSPO).

How do I stop it happening again?

• Ask your network about extra security on your account, such as a PIN or password needed for any SIM change.
• Use an authenticator app or your bank's app approval instead of text codes wherever possible.
• Don't share personal details with callers claiming to be your bank or network. The CCPC and FraudSMART both warn about this kind of "vishing" call.
• Limit what you post on social media: date of birth, address, phone number.
• Turn on two-step verification in WhatsApp and your email.

Frequently asked questions

Is it always fraud if I lose signal? No. Network outages, a damaged SIM or a phone setting are far more common. But if it happens suddenly in a place where you always have coverage and it doesn't come back, ring your network from another phone to rule it out.

Can they do this with an eSIM? Yes. Fraudsters can request an eSIM activation in the same way. The response is the same: ring your network and your bank straight away.

My bank sends codes by text. Should I change that? If your bank offers approval through its app or an authenticator, use it. It's more resistant to SIM swaps than codes sent by text.

How did they get my banking password? Usually through an earlier phishing text, email or call, or a data breach. That's why it's important to change your passwords after any suspected fraud.

In short

Sudden "No service" where you always have coverage deserves a phone call from another line. Ring your network and your bank immediately, change your email password and check your accounts. If money has been taken, report it to the Gardaí and your bank. And report any suspicious number that contacted you beforehand in the NoCall spam numbers directory.