I love me a thermal bath. Been lucky enough to visit some great ones in Hungary, Canada and…read moreIceland.
This is right up there in terms of facilities, cleanliness and general enjoyment. I visited twice during my week in Stuttgart. The first time I used both the swimming baths and sauna area (on 2nd visit, sauna was female only. Check before visiting). Sauna area is nude. Something I've never experienced before but quickly became used to it.
Make sure you check the 'ausguss' timetable in the sauna area for when you can take part in the ritual of having red hot steam blasted into your face by a towel twirling attendant (more fun than it sounds). Swimming area is not nude and has a brilliant outdoor section with a small, fast flowing lazy river. I visited both Leuze and Canstatt mineral baths during my time in Stuttgart and in my opinion, Leuze has the best sauna area but Canstatt has the best and more modern swimming area.
Definitely worth a visit during your time in Stuttgart and I hope I can come back one day.