Spas with upscale

Miami, Florida

A beachfront resort spa in North Beach, Miami with cryotherapy, a floating salt bath, sauna, steam and a cold plunge, open to walk-ins and day-pass guests.

Napa Valley, California

Adults-only hotel spa in Napa Valley with a co-ed thermal circuit of sauna, steam room and cold shower, open daily 10am–6pm; day passes available.

Calistoga, California

A 20,000-square-foot resort spa in Calistoga with five geothermal pools, Calistoga mud treatments, and a day pass for non-hotel guests.

San Antonio, Texas

Full-service resort spa at the Hyatt Regency Hill Country in San Antonio, with thermal circuits, cold plunge and day passes open to non-guests.

Sayulita, Nayarit

A hillside boutique hotel spa outside Sayulita with sauna, steam room, cold plunge and ocean-view pool, open on a day-pass basis.