All it takes is a slight depression of the chronograph pusher and water will flood in. can accidentally happen and by the time you realize it, well, too late. I've tested my Skyland Avenger and it's passed 6 ATM, my Daytona to 3 ATM, but I will never intentionally swim with either for this reason. I was bored one day and was curious if they were reasonably waterproof, which they are... that being said I won't swim with them. period.