If theft detection didn't work, there are at least two backups. Offline Device Lock activates if the Internet connection is disabled on your phone. And, using another device, you can use Remote Lock at android.com/lock to quickly lock your device with a phone number and a security challenge. It's a faster way to secure your device while you use Find My Device to locate and further lock your gear.

Those three key features—Theft Detection Lock, Offline Device Lock, and Remote Lock—are not exclusive to Android 15 but are rolling out along with its release. Users on Android 10 or higher should get a Google Play Services update to enable the features, though they'll have to be turned on in the device settings.