If you ever misplace your device—whether it’s lost or you think it might have been stolen—you should immediately use Mark As Lost in the Find My app.

When you Mark As Lost, this locks your screen with a passcode and lets you display a custom message with your phone number to help you get it back. You can also remotely erase your device if needed, and your custom message continues to display even after the device is erased.

While Activation Lock works in the background to make it more difficult for someone to use or sell your missing device, Lost Mode clearly indicates to anyone who finds your device that it still belongs to you and can’t be reactivated without your password.

To mark a device as lost, sign in to icloud.com/find. Or use the Find My app:

Open the Find My app. Tap the Devices tab, then choose a device from the list. Tap Activate under Mark As Lost and follow the instructions on the screen.

Learn more about what to do if your device is lost or stolen. If your iPhone is covered by AppleCare+ with Theft and Loss, the theft and loss coverage requires you to have Find My iPhone enabled on your device at the time it's lost or stolen.