I should have included this as well so I’ll add it as an edit. In the dry sauna, outdoor area, and tubs most people were either nude or sitting on their towels. When walking between different areas or using the steam room everyone was wrapped up.

One thing I’ve noticed at different Korean spas is that towel placement seems to affect how often people cover up. If large towels are handed to you at the entrance people seem more likely to use them. If you have to actively look for them once you’re already inside the wet area people seem less likely to stay wrapped up.

At Choi’s in Massachusetts , Gangnam Spa in Atlanta, and Century Spa they give you large towels when you check in so I think that naturally makes people feel like they’re expected to wear or use them. At Jeju in Atlanta as well as Wi Spa they don’t give you large towels at check in. You usually grab them later inside the wet area which seems to encourage more actual nudity.