Spas with thermal pool

Calistoga, California

A 1952 Calistoga hot springs resort with three mineral pools at 85, 95 and 104°F, mud baths, overnight rooms and a day-pass option.

Scottsdale, Arizona

Hotel spa at the mid-century Hotel Valley Ho in South Scottsdale, with sauna, steam room and two pools, open to hotel guests only.

Koh Samui, Surat Thani

Kamalaya Koh Samui is an adults-only destination spa and wellness retreat on Laem-Set Rd with over 100 treatments, thermal circuits and multi-day health

Chicago, Illinois

Upscale day spa in Lincoln Park, Chicago, where booking any treatment unlocks all-day access to a hydrotherapy circuit, thermal suite and outdoor terrace.

Chicago, Illinois

A West Town day spa built around a beer soak, with sauna, steam room, salt room and thermal pool for couples or solo visits.

New York City, New York

A five-treatment-room hotel spa inside The Greenwich Hotel in Tribeca, built around a heated pool and Japanese-influenced design.

Tucson, Arizona

A resort day spa at Westward Look in Tucson with a thermal pool, sauna, steam room and cold plunge, open daily 9am-6pm by reservation.

Rocky River, Ohio

Massage-focused day spa in Rocky River offering couples treatments, sauna, steam room and thermal pool, open daily by appointment.

Austin, Texas

Day spa in Steiner Ranch, Austin, offering sauna, steam room, thermal pools, cold plunge and a signature scalp treatment for adults, open Monday through

Centreville, Virginia

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.

Sedona, Arizona

Day spa in West Sedona with sauna, steam room and a thermal pool, open daily by reservation and set up for couples treatments.

Palm Springs, California

Boutique hotel spa in Desert Hot Springs with two natural mineral hot spring pools, day passes, and overnight rooms that include breakfast.

Palm Springs, California

Downtown Palm Springs day spa built around a natural hot mineral spring, with private mineral baths, sauna, steam room and massage.

Carmel-by-the-Sea, California

A hotel spa at Quail Lodge and Golf Club in Carmel-by-the-Sea with a steam room, three private fitness cabanas and a heated outdoor pool, limited to hotel

Milwaukee, Wisconsin

East Town Spa in Milwaukee's Juneau Town combines a full-service salon and med spa with a thermal circuit of sauna, steam, pools and cold plunge.

Ubud, Bali

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

Tucson, Arizona

Day spa in Tucson's La Encantada shopping center with a thermal circuit of sauna, steam room, cold plunge and soaking pools.

Tucson, Arizona

Lakeside Spa at this 398-room desert resort in Tucson is open to hotel guests only, with two heated pools, a Jacuzzi and mountain views of Catalina range.

Hot Springs, Arkansas

A café and lounge inside Thai-Me Spa in downtown Hot Springs, with outdoor mineral soaking spas, cold plunge and sauna access nearby.

Fort Lauderdale, Florida

Hotel spa at The Atlantic Resort on Fort Lauderdale Beach with sauna, steam room, cold plunge and thermal pool, for overnight guests only.

Minneapolis, Minnesota

A moderate-priced day spa in Minnetonka with a sauna, steam room, thermal pool and cold plunge, set up for couples and adults-only visits.

Charlotte, North Carolina

A moderate-priced day spa in Charlotte's SouthPark area with a sauna, steam room and thermal pool alongside massage, facial and body-treatment menus.

Hot Springs, Arkansas

A day spa on Central Avenue in Hot Springs with outdoor mineral soaking tubs, cold plunge, infrared sauna, massage and an on-site café.

Santa Fe, New Mexico

Hotel spa at La Fonda on the Plaza in downtown Santa Fe, with a heated outdoor pool, hot tub, fitness center and relaxation lounge for guests of the hotel.