How to pair your Apple Watch with a new iPhone

Before you switch your Apple Watch to a new iPhone, update your old iPhone to the newest version of iOS that’s available.* You should also update your Apple Watch. It could take from several minutes to an hour for the updates to complete. You might want to update overnight or wait until you have time, and make sure that both of your devices are charged.

* You might see that your iPhone is up to date on its current version, and there’s an update available. For example, even if your iPhone is up to date on the latest version of iOS 14, there might be an option to update to iOS 15.