If a thief always steal iPhone from your bag or even snatching it from your grasp, panic will immediately arise. You may also have more to worry about than just the cost of replacing the phone. What if they saw me enter the passcode and now have easy access of all my messages, photos, and sensitive information? While it’s certainly not a good idea to get your smartphone, turning on Apple’s Stolen Device Protection can quickly cut off thieves’ access to your smartphone data. This feature is not automatically enabled and must be activated before the crime occurs.

First released as part of iOS 17.3, Stolen Device Protection essentially adds an extra layer of security to your smartphone when the device is in a place you don’t visit often. Here’s a quick guide to what the software does and what steps are required to turn it on.

For a deeper dive into Apple’s anti-theft software, check out the WIRED security reporter Matt Burgess’s article about the feature from last year. If you have an Android phone, read my user guide Android theft detection parts.

What Does Stolen Device Protection Do?

The feature is specifically designed for situations where a criminal not only takes your iPhone but also knows your passcode and can unlock the device. If they physically take your phone from you and take it to a location you don’t visit often, then the Stolen Device Protection security measures start kicking.

The main thing that triggers the feature is that it starts to require your Biometrics in Face ID to access any sensitive part of the phone, such as using your Keychain passwords, viewing your saved payment information in Safari, and disabling Lost Mode. Even if thieves know your passcode, it’s no longer available as a backup option; Face ID is required for full access. It also prevents thieves from easily erasing all your phone data so they can sell it, as that method also requires FaceID.

In addition to forcing biometric authentication, Stolen Device Protection adds a security delay period for changes to the phone’s security features. If the thief wants to sign out of your Apple ID or turn it off Find My iPhonefor example, they can’t just hold the phone in front of your face for a few seconds while they flee the scene of the crime. With the automatic security delay feature, you have to wait an hour to make major security changes to the device, and you have to confirm your biometrics at the beginning as well as at the end of this process.

How Do I Turn On?

Before you can turn on Stolen Device Protection, you first need to set up some other basic features on your smartphone. You may already have Face ID and a passcode enabled on your Apple device—both of which are required for the feature to work.

Next, you need to check if two-factor authentication is enabled enabled for your Apple IDwhich is a good idea even if you are not using Stolen Device Protection. Check to see if you’ve already used it by going to Settingstap on your name above, and then select the Sign-In & Security tab. You should see if 2FA for your Apple ID is on or off in the middle of this screen.

The last piece of software you need to activate on the iPhone is Important Locations. It tracks the places you visit often, so your phone knows if it’s in a familiar or unfamiliar place. According to Applethe data is end-to-end encrypted and unreadable by the company. Important Locations are somewhat buried in the menus—find them by opening SettingsTHEN Privacy and Securityand Location Services. After that, scroll until you see the System Services tab. selection Important Areasand you’ll probably be prompted to unlock it with Face ID. On the next page, move the toggle to the right to finish enabling the feature.

Phew! OK, now you are ready to start using Stolen Device Protection. And, lucky for you, after all the prep work, the last step is easy. TOMORROW Settings one more time, then Face ID and Passcodeand enter your passcode. Scroll to the middle of the page, select the Stolen Device Protection tab, and move that toggle to the right.