I am traveling an I prefer to go naked in the sauna and hot tub, but how can I know the policy? I would also prefer not to ask someone.
I don’t know where you are travelling to, so the following is generic advice for anywhere on the planet.
Check the terms and conditions or policies on the website or displayed in the club.
Check any pictures on the website – but bear in mind that it’s very rare for a club that allows nudity to show nudity in the pictures.
Turn up and play it by ear.
If people can be naked outside the sauna or beside the hot tub, it’s OK inside. This means German-style mixed thermal suites, oriental bath houses and some changing room based facilities.
Hot tub:
If it’s beside a pool, assume a swimsuit is required.
If it’s in a separate area to the pool and private, assume a swimsuit is not required.
If it’s in a thermal suite where all or most people are naked / covered in towels, it is optional.
Ditto for changing rooms.
If in doubt, wear a swimsuit.
Sauna:
Even saunas that declare that swimwear is required will usually allow you to be covered by a towel instead. In hotel based health clubs there are a lot of people who are not regulars and will not be aware of the policy either. You should always have a towel underneath you if you are not wearing a costume as sitting directly onto the benches will nearly always produce a comment from other users whereas nudity is often ignored.
Always be prepared to cover up if requested.
If in doubt, wear a towel.