Can one wear a swim suit while in onsen? (I've heard that no)?

Question:

Answer:

I've never seen anyone wear a swimsuit in an onsen (except maybe on TV . . . but even when someone is reporting from an onsen, they often do it nude . . . .). The thing is, when you go into the bath, you are supposed to be ABSOLUTELY clean. If you are wearing a swimsuit, you can't really scrub those parts of yourself, and also, if there's soap trapped in the swimsuit, it gets in the bath and dirties it for everyone. I think it would be extremely weird and somewhat rude to get into a Japanese onsen while wearing a swimsuit.