Hello ! I have question if when entering the sauna is it mandatory to be fully undressed? I'am asking because when i was in a NJ spa we where supposed to be naked which made me fell uncomfortable

The main floor saunas are coed and you need to be dressed with their uniform on top of your bathing suit. There are more saunas in the women and men bathrooms, those are sex specific and most people go in naked, I guess you can enter with a bathing suit too but, not sure.

Nope they said they have separate ones they have a side for the ones who prefer to be naked but other than that u can have ur bathing suit