If your Apple Watch device is currently paired to your old iPhone, follow these easy steps to find out how to connect Apple Watch to new iPhone:
- Back up your old iPhone to iCloud
- Set up iPhone and on the Apps & Data screen, choose to restore from an iCloud backup and select the latest backup
- Continue and when the option becomes available through the setting up process, choose to use your Apple Watch with your new device
- Once completed, your Apple Watch will prompt you to pair it with the new iPhone.
- Choose OK on your Apple Watch and enter your passcode.