To unpair your Apple Watch from your old iPhone, follow these steps:
- Open the Apple Watch app on your old iPhone.
- Tap the My Watch tab at the bottom of the screen.
- Tap All Watches at the top of the screen to see your paired watches.
- Tap the circled i (info) button next to the Apple Watch you want to unpair.
- Scroll down and tap Unpair Apple Watch.
- Enter your Apple ID password when prompted to disable Activation Lock.
- If you have a cellular model, choose whether to keep or remove your cellular plan.
- The unpairing process will begin, during which your Apple Watch will back up its data to iCloud automatically. Once complete, the watch will be erased and unpaired from your iPhone.
If you plan to pair the watch with a new iPhone, you can restore your data from the backup during setup. If you are selling or giving away the watch, you can also reset it directly on the watch by going to Settings > General > Reset > Erase All Content and Settings after unpairing
