Best watch for swimming

Why this one

Start with the thing that ruins most watches: the depth on the dial is not a swimming depth. Those figures come from a static pressure test in a laboratory, with the watch held still in cool water. Swimming is neither static nor cool. Pushing an arm through water briefly generates pressure far beyond the depth you are at, and warm water expands seals. This is why a watch marked 30 m should never be swum in, why 50 m is for splashes and rain rather than lengths, and why 100 m is the sensible floor for a pool. The second thing almost nobody is told: the crown matters more than the number. A push-in crown is a hole in the case held shut by a gasket. A screw-down crown threads closed. A 100 m watch with a push-in crown is more fragile in real swimming than a 200 m watch that screws shut. Which is why this is the pick. The Seastar is rated to 300 m with a screw-down crown, a sapphire crystal and a proper unidirectional diver's bezel, and it is quartz — which for swimming is a feature rather than a compromise, because there is no winding routine to forget and no accuracy lost while it sits in a drawer between weekends. Two honest drawbacks. At 45.5 mm it is a genuinely large watch and will look it on a slim wrist — if that matters more than the rating, the 40 mm Seastar is the same watch in a size more people can wear. And the chronograph pushers do not screw down, so while the case is rated to 300 m, do not operate them underwater. That is true of nearly every dive chronograph, and it is the reason purists buy a plain three-hand diver instead.