I'm sorry but I don't quite understand. You will be wearing a chastity device on your man parts? That's fine. But what does that have to do with having to wear a bathing suit?
We've seen some men wear their bathing suits in the hot tub - not many, mind you, but there has been a few who choose to. But the suits don't stay on long as soon as they realize they are in the minority. Most people follow the crowd.
But you, my friend, may start a new trend if you feel the urge to forgo the bathing suit. When are you going? Hope it's when we're there.