Open the Watch app on your iPhone
Tap My Watch
Tap All Watches
Tap the info button next to your Apple Watch
Tap Unpair Apple Watch
Enter your Apple ID password if prompted
Confirm unpairing
Wait for the Apple Watch to be removed from your iPhone
Open the Watch app on your iPhone
Tap My Watch
Tap All Watches
Tap the info button next to your Apple Watch
Tap Unpair Apple Watch
Enter your Apple ID password if prompted
Confirm unpairing
Wait for the Apple Watch to be removed from your iPhone