Normal, probably. I like Water but I can't swim or anything - not that that's stopped certain Water-type Pokémon.
All water pokemon can swim
I've never seen fossils, Palkia, Arceus-Water or Rotom-Wash in water in any game so I can't really say whether they can or not. Then there's dex entries about Surskit skating across water rather than swimming, Magikarp going with the current and Qwilfish finding swimming "challenging" despite all three having Swift Swim (although only Qwilfish can learn any of Surf, Dive or Waterfall). Phione allegedly drifts like Magikarp, but then Pokédex gameplay-story segregation. Remoraid, lazy as it is, hitches on to Mantine, which would probably describe my reliance on floats and the like pretty well.