Thap Ba Hot Springs is the best-known of several mineral spring complexes on the outskirts of Nha Trang, about 5 km north of the city centre. The main draw is the mud bath — you lower yourself into a tub of warm volcanic mud, soak for about 20 minutes, rinse off, and then relax in a mineral water pool. The whole experience is unashamed tourist infrastructure but works perfectly well as a couple of hours of relaxation.
Tickets cover different combinations of mud bath, mineral pool access, and waterslides (aimed at families). The complex is landscaped with gardens and food stalls. Go on a weekday to avoid the larger tour groups. A second complex, I-Resort, offers a similar experience a short distance away.