Will Apple Watch 5 pair with iphone 6sPlus?

You have to upgrade the iPhone 6s Plus to iOS 13. Then you can pair with a new Apple Watch.

But be VERY SURE you have a 6s, because the new Apple Watches will Not pair with an iPhone 6 or 6 Plus or older, and the iPhone 6 and 6 Plus Cannot be upgraded to iOS 13.

If you really have an iPhone 6 Plus, I would strongly suggest you return your Apple Watch series 5 within the Apple 14 day return period for a full refund. Then you can take your time to decide when you want to get a newer iPhone. A new Apple Watch can then be purchased when you have an iPhone that will work with the Apple Watch.

honeycrisp402 wrote:

I have an iphone 6sPlus. iOS 12.4.2. Phone won't update to iOS 13. My husband bought me an Apple Watch 5. Can't seem to get them to pair. Any suggestions?

Go to Settings>General>About>Model Number. What does it say? It is likely that you actually have an iPhone 6 Plus. If that's the case, Bob's advice is spot on.