Any respectable tracker should be able to accompany you on a run in the rain without crapping out. At this point, almost every tracker goes past splash and sweat resistance to hit a 5 ATM rating, meaning the device can withstand pressure equivalent up to 50 meters (164 feet). These should be fine to wear in the shower, in the ocean, or in a hot tub. Swimmers have a bit more to consider than the waterproof rating. Look for a tracker with built-in GPS that can not only follow you underwater, but accurately track your laps and pace. Dedicated modes for pool swims and open water swims are ideal. For more guidance on fitness trackers for swimming and other water sports, check out our roundup for the best waterproof fitness trackers.