I lost my watch but did not set up find my what can I do to report it lost

If you didn't turn on Find My before your Apple Watch was lost or stolen and your watch isn't connected to Wi-Fi, cellular, or your paired iPhone, you can't use it to locate your device. However, you can use these steps to help protect your information:

1. Place your Apple Watch in Lost Mode. When your watch is in Lost Mode, your passcode is required before anyone can turn off Find My, erase your watch, or pair it with another iPhone.
2. Change your Apple ID password. When you change your Apple ID password, you can prevent anyone from accessing your iCloud information or from using other services from your missing device.
3. Report your lost or stolen device to local law enforcement. Law enforcement might request the serial number of your device. Find your device serial number.

Find My is the only way that you can track or locate a lost or missing device. If Find My isn't enabled on your watch before it goes missing, there is no other Apple service that can find, track, or otherwise flag your device for you.