If you have a Series 2 or later Apple Watch and want to take it into the pool with you, you’ll want to put your Apple Watch into water mode (a feature that’s been around for years, but one that easily escapes notice).
If this doesn’t mean anything to you, take a minute to watch this short Instagram video. It’ll show you what to do.
This is weird advice. Mine has never failed to detect that it’s in the water and switch itself.