Spas with thermal pool

Day spa in Plainfield, IN offering facials, massages and body-sculpting treatments alongside a sauna, steam room and thermal pool, reservation required.

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.

A 24-hour Korean bathhouse in Duluth with a $30 day pass, sauna rooms, cold plunge, thermal circuits and a junior Olympic pool.

North Scottsdale day spa with massage, facials, sauna, steam and a thermal pool, plus private suites for couples and groups.

Adults-only spa inside the all-inclusive Ocean Riviera Paradise resort in Playa del Carmen, with sauna, Turkish bath and four treatment options via day pass.

Hotel spa at the Inn at Eagle Mountain in Fountain Hills with sauna, steam room, pools and a $69 60-minute massage as its signature treatment.

A 38,000-square-foot resort spa at JW Marriott Desert Springs in Palm Desert offers day passes, saunas, a saltwater lap pool and couples suites.

Hotel spa and pool deck at a moderate-price resort in Osprey, Florida, with sauna, steam room and thermal circuits for overnight guests.

A Korean jjimjilbang in Centreville, Virginia, with multiple saunas, a bade pool, steam rooms and a restaurant, open daily 8am–10pm with walk-in access.

An adults-only wellness retreat on Ubud's Ayung River offering multi-day healing programmes, thermal circuits and plant-based cuisine by reservation only.

A hotel spa at the Handlery Hotel in Mission Valley, San Diego, with sauna, steam room, cold plunge and thermal pools for guests.

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.

A resort spa inside the Iberostar Waves Tucán in Playacar offering sauna, Turkish bath and jet-pool treatments, open to day-pass visitors 16 and up.

Hotel spa near Bell Rock in Sedona with sauna, steam room, cold plunge and pools, open to resort guests only.

An all-inclusive beachfront resort spa in Huatulco with a sauna, steam room and thermal pools, open only to hotel guests.

A hotel spa on Mission Bay in San Diego with sauna, steam room, cold plunge and thermal pools, open only to resort guests.