New Google Fi 'Number Lock' setting protects against SIM swaps

Google Fi Wireless has a new Number Lock feature that provides an “additional layer of protection against illegal SIM swaps.”

“SIM swapping happens when someone is able to steal your phone number by convincing your carrier to port your phone number over to a SIM card they own. For example, someone may call your carrier, pretend to be you, and convince your carrier that you have lost your phone and need to move your number to a new phone.”

Google

When Number Lock is enabled, “you can’t transfer your number to a new device or carrier while this lock is active.”

To enable, go to the Google Fi website (fi.google.com/account) and select your user (if you have multiple as part of a group plan). Go to Phone settings > Privacy & security > Number lock.

Tap “Sign in to manage Number lock” and confirm your Google Account credentials to enable the toggle.

If you ever want to “transfer your number to a new device or port to another carrier,” return to that page, which is not available in the Android or iOS apps. Since the inconvenience is minimal, enabling Number Lock should be a good idea for most users.

Outside of this feature, transferring a number out of Google Fi is made more difficult by existing Google Account protections, especially with two-factor authentication enabled, that require you to be signed-in and authenticate. However, the issue is a nefarious party targeting the T-Mobile backend, which is what looks to have happened last year. A good precaution in general is disabling SMS-based 2FA when possible.

We’ve reached out to Google for more information on how Fi Number Lock works.