My I watch was connected to my other iPhone and it’s stolen how do I find it

If you know the Apple ID Password and Email you are signed in on the lost devices then you can go to this link https://www.icloud.com/ then follow these steps

1. sign in to your account using your Email associated Apple ID on the iPhone and Apple Watch and the password to that account
2. Once you are logged in click the waffle patterned dots in the upper right hand corner of your screen, then click the find my icon
3. You will need to enter your the Apple ID password again to gain access to Find My
4. once you enter in the password correctly you should see a map that shows all devices connected to that Apple ID

I hope this helps you.