Ten years ago your mobile number was just how people called you. Today it's quietly become one of the most important pieces of information you own. It's the backup key to your email, the second step when you log in to your bank, and the way dozens of apps confirm it's really you. That makes it valuable to you, and to criminals.
Everything that's tied to your number
- Banking: one-time passcodes for payments and new devices.
- Email and social media: password resets and login checks.
- Shopping and delivery apps: account recovery and order updates.
- Messaging apps: WhatsApp, Signal and others use your number as your account.
- Health and government services: appointment reminders and sign-in codes.
Why criminals want it
If someone can receive your texts, they can often reset your passwords and approve payments. There are two main ways they try:
SIM swap fraud
A criminal contacts your network pretending to be you and persuades it to move your number to a new SIM they control. Your phone suddenly loses signal, and your texts start going to them.
Tricking you into handing over codes
Far more common is simply asking. A caller pretending to be your bank, or a WhatsApp message from a "friend", asks you to read out or forward a code you've just been sent. That code is often the key to your account.
How to protect your number
- Never share a code you didn't ask for. If a code arrives that you weren't expecting, someone is probably trying to get into your account.
- Add a PIN or password to your mobile account. Most networks let you set one so nobody can make changes without it.
- Turn on two-step verification in your apps, and where possible use an authenticator app or passkey instead of SMS codes.
- Act fast if your signal vanishes for no obvious reason. Contact your network from another phone and ask whether your SIM has been changed.
- Be careful where you publish it. The fewer places your number appears, the fewer marketing lists and scam lists it lands on.
When your number is used against you
Because so much depends on your phone, scammers often call it first. If an unknown number rings and starts talking about your bank, a parcel, or a security problem, hang up. Look the number up on Who Called Me Check to see what other people have reported, and contact any organisation directly using a number you trust.
Not sure about a call you had?
Look the number up to see what kind of line it is, where it's from and what other people said about it.