Uhm, I can swim, yeah. That's about as far as it goes.
I don't really know how to swim properly, like I don't know how to do the backstroke or the breaststroke or whatever. But I can doggy paddle and float on my back. I have never been SCUBA diving and don't know how to do a proper dive (though I'll dive off a low board or the side of a pool). I think I've had a swimming lesson or two as a kid? But it was probably more supervised playing in a pool? I don't really like the ocean but I go in it once in a while if it's there.
I've played volleyball in a pool, but never in any organized way. (I like it, though! I actually like volleyball in general.) I've never been waterskiing or anything like that. I don't know if it counts, but I have been canoeing. I got a certification in it with my parents and my sister when I was pretty young, and continued to go on short canoe trips with friends/family as an adult (but haven't done that in years).