Zippered pockets are better than nothing, but not magical.

They help, but don’t rely on them if you’re actually swimming hard.

Any decent swim trunk with a back zippered pocket—Patagonia Baggies, Hurley, Quiksilver—will keep your keys and cash secure while you walk around or float. The zipper adds resistance and makes it harder for things to fall out accidentally.

But water forces its way through zippers. If you dive, bodysurf, or swim laps, that pocket is