Yes. They're basically a thin PVC plastic. You could run them through the dishwasher if you wanted.
Also - fun fact - you can use a dry erase marker for signatures and wipe it off. Well, it'll take a bit more effort than a dry erase board, but it works.
Yep, Bicycle Prestige is extremely durable - it's made of plastic, not paper, so it won't absorb water. That said, it doesn't handle, fan, Faro, or feel the same way as theory11 decks (or normal Bicycle decks) typically do. If you need a deck that's resistant to water (or humidity), though, it should be perfect.