They are completely water proof as are wetsuits made of the same material as long as the seams are fully stitched and welded. The only way that water gets into a wetsuit is via the neck wrists, ankles and zip and then only enough to form a warm layer between your body and the suit. You wont have any openings in the water with waders(or shouldn't).Im thinking of buying a pair of neoprene waders, whilst they look like a wetsuit, and i know this may seem a bit of a stupid question but are they waterproof ?as wetsuits are obviously not