In 2025, phone numbers have become woven into nearly every part of our digital lives. Whether you’re creating accounts on e-commerce sites, managing online banking, accessing health services, or logging in to social networks, your phone number is the gateway. It helps reset forgotten passwords and powers two-factor authentication codes that keep your accounts secure.

But if a hacker gets hold of your phone number, they can essentially impersonate you.

With control over your number, attackers can infiltrate your online accounts or manipulate automated phone systems to convince customer service representatives they’re speaking to you. In some cases, a stolen phone number can even be used to breach a company’s internal network and retrieve confidential information.

That’s why it’s more important than ever to protect your number against SIM swapping — a cyberattack where someone fraudulently transfers your number to a new SIM card. The good news? Locking down your number has never been simpler.

SIM swap attacks typically begin when a criminal contacts your mobile carrier, pretending to be you. By using publicly available personal details — like your name and birth date — the attacker convinces support staff to port your number to a SIM card they control. Once the transfer is complete, your number is live on their device. From there, they can send messages and make calls in your name.

Often, the only clue that something is wrong is if your phone abruptly loses service without explanation.

These attacks exploit gaps in the internal security processes at phone companies, where representatives can make account changes without always verifying the customer’s consent.

To fight back against these social engineering scams, the three largest U.S. mobile carriers — AT&T, T-Mobile, and Verizon — have launched security tools that help prevent unauthorized account takeovers and SIM swaps. However, these protections may not be turned on by default, so it’s worth taking a few minutes to review your account settings.

AT&T: In July, AT&T rolled out its free Wireless Account Lock, designed to block SIM swapping attempts. “The feature allows AT&T customers to add extra account protection by toggling on a setting that prevents anyone from moving a SIM card or phone number to another device or account.” You can activate this safeguard in the AT&T app or through your online account dashboard. Be sure your account is secured with a unique password and multi-factor authentication.

T-Mobile: T-Mobile gives customers the option to lock their accounts against unauthorized SIM swaps and number porting at no cost. To enable this, the primary account holder must log in to their T-Mobile account and switch on the protection settings.

Verizon: Verizon offers two layers of defense: SIM Protection and Number Lock. These features stop SIM swaps and unauthorized phone number transfers. You can enable them through the Verizon app or the account portal. Verizon notes that if you disable these protections, any account changes will be delayed by 15 minutes, giving legitimate users time to undo suspicious activity.

Take a moment to check whether these safeguards are active on your account. While they aren’t always advertised prominently, they can make all the difference in keeping your phone number — and your identity — safe