WatchOS - Locating the MAC Address of an Apple Watch
Step by step instructions for locating the MAC/WiFi address of a WatchOS device that includes a WiFi chip.
Note: Only select Apple Watch products have WiFi available. These instructions will only work for Apple Watch/WatchOS devices with WiFi built in.
Locate and tap the Watch app.
The WiFi/MAC address is listed by the Wi-Fi Address section.
If you are looking to register the Apple Watch on UWNet, follow the instructions for registering a device without a browser once you have located the MAC address: Wireless UWNet - Register a Device Without a Browser