Your phone number is the skeleton key to your digital life, and carriers have spent years handing out copies to anyone with a decent script. Resetting a bank password, recovering an email account, approving a crypto withdrawal: All of it can run through a text message sent to a number that a call-center rep can reassign in minutes.

The good news is that all three major U.S. carriers now let you lock your number with a toggle. Here's how the attacks work and where to find each switch.

How SIM swaps and eSIM hijacking work

A SIM swap starts with research. Attackers collect your name, address, and account details from data breaches or phishing, then contact your carrier pretending to be you. If they convince someone to move your number onto a SIM they control, your calls, texts, and two-factor codes go to them instead.…