I have bought my first Apple Watch second hand from CEX, and my wife is considering buying one for herself. I have the series 8, which is the latest model that Apple has released which works fine with my iPhone SE 2020. However, my wife has an iPhone 6S. This blog post details which phone works with which Apple Watch and iOS version.
Apple watches pair with iPhones, this is because of the handoff features as well as in the cellular models you can share an e-sim between the phone and watch so you don’t need your phone with you when you work out. It can make and receive calls, messages and other things while you work out which is pretty cool.
Watches with Android
Pairing an Apple Watch with Android is tricky but not impossible. You must pair the Watch to a compatible iPhone and then turn the Watch off, remove the sim card from the iPhone and put it in the Android phone, then power on the Watch.
Watch versions and iPhone versions
Any Watch can pair with a modern iPhone running iOS 16 and newer, but older iPhones that run older iOS versions won’t work with newer Watches.
Series 8 Ultra
SE (2nd Gen)
SE (1st Gen)
With the planned release of Apple Watch series 9 in September, I’m guessing the minimum iPhone version will be pushed to iPhone XS, in line with iOS 17 dropping the iPhone 8 and X.
iPhone 8 (and X) will be 6 years old in September, and Apple concedes that the iPhone has a 3-5 year lifespan (compared to 2-3 year lifespan of an Android phone)