Whatever you feel comfortable wearing; if you don't mind being naked, go naked but sit on a towel. A random persons sweat on the naked bum isn't nice! But if you know other people will be in there and you don't want your bits hanging out, wear a bikini or swimming costume. A one piece might get a little warm and uncomfortable with the sweat
so...yeah, I know this should really be in the fashion thread, but more people will see it here
I'm off on holiday to Finland in the morning, and we get a sauna including in the price every day, but wtf do you wear in a sauna?!
swimming stuff? nothing? a towel?
pos rep to the first helpful answer
In scandinavia its nothing... My friend when he went to sweden to meet his father in law went in with shorts on only to be faced with his entire inlaws... starkers.