Protecting Your Cell Phone Number from SIM Swap Attacks: Essential Strategies

In the year 2025, phone numbers are ubiquitous. We depend on them for signing up for various accounts, including those in retail, banking, social media, and healthcare. Phone numbers are essential for resetting passwords and receiving two-factor authentication codes, thereby bolstering account security.

However, if someone successfully steals your phone number, they could impersonate you.

With access to your phone number, a hacker can start infiltrating your online accounts and even trick automated systems into thinking they are you when reaching out to customer support. A compromised phone number can give them unauthorized entry into a company’s internal network, granting them access to sensitive data and files.

This highlights the necessity of protecting your phone number from SIM swapping—a cyber threat in which a hacker gains control of a victim’s phone number. Luckily, safeguarding your number has become easier than ever.

Typically, SIM swapping happens when a malicious hacker pretends to be a specific customer while calling a phone carrier. They use information obtained online, such as the customer’s name and birthdate, to persuade a customer support representative to transfer that number to a different SIM card or carrier. Upon completion, the hacker activates the victim’s phone number on a SIM card they control, enabling them to make calls and send texts as though they were the actual victim.

Often, the first sign of this type of attack is the victim unexpectedly losing cell service without any explanation.

SIM swap attacks exploit weaknesses in the security measures of cellular providers’ internal systems, allowing support representatives to make changes to customer accounts without direct approval from the account holder.

To reduce impersonation risks and social engineering tactics, three major U.S. carriers—AT&T, T-Mobile, and Verizon—have introduced security features aimed at complicating a hacker’s ability to manipulate customer accounts, particularly when it comes to porting phone numbers.

Take a moment to check your phone carrier’s account; these features are often not widely advertised and may not be activated by default.

AT&T

In July, AT&T rolled out its free Wireless Account Lock security feature designed to block SIM swaps. This feature allows AT&T customers to enhance their account security by enabling a setting that prevents any transfer of a SIM card or phone number to another device or account. Account holders can use the AT&T app or online account portal to activate this feature, so make sure your account is secured with a strong password and multi-factor authentication.

T-Mobile

T-Mobile allows customers to block SIM swaps and unauthorized number port-outs for free through their online account. The primary account holder must log in to modify the settings, toggling them on or off as needed.

Verizon

Verizon provides two security features—SIM Protection and Number Lock—that help prevent SIM swaps and phone number transfers, respectively. Both functionalities can be enabled via the Verizon app and the online account portal by the account owner or manager. According to Verizon, deactivating the feature may cause a 15-minute delay before any transactions can take place—offering an additional safety net for the legitimate account holder to reverse any unwanted changes.