Can you wear bathing suits?

I've never seen anyone in the women spa area with a bathing suit, everyone is as the day they were born. You cover up in the common area upstairs. Hope this helps

There's a sign in the men's area, "no bathing suits allowed." I assume it's the same in the woman's.

That is the common etiquette of all korean spas, keeps the waters cleaner without soap transfered by bathing suits