Spas with thermal pool

Scottsdale, Arizona

Adults-only hotel spa at W Scottsdale with thermal circuits, sauna, steam, cold plunge and a robotic Aescape massage option.

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.

Banff, Alberta

Luxury hotel spa inside Fairmont Banff Springs offering thermal pools, steam rooms and treatments, open daily with day passes for non-guests.

Húsavík, Northeastern Region

Geothermal seawater baths built into the cliffs above Skjálfandi bay in Húsavík, with walk-in day passes and views toward the Arctic horizon.

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

Thatcher, Idaho

A riverside hot springs in Thatcher, Idaho, with outdoor thermal pools, day passes, and overnight stays in yurts, cabins, or tents.

Olmué, Valparaíso

A boutique lodge and spa in the Olmué valley, about 80 minutes from Santiago, with a thermal pool, outdoor baths and day passes for non-guests.

Amalfi Coast, Campania

An adults-only day spa in Minori on the Amalfi Coast built around a thermal pool, open daily 11am to 8pm by reservation.

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.

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

Brežice, Posavje

A large thermal water park in Brežice, Slovenia, with a year-round indoor pool riviera, an adults-only sauna zone, and seasonal outdoor slides.

Orlando, Florida

Hotel spa at the Rosen Centre on International Drive in Orlando, offering massages, facials, nail care and access to a steam room, pool and fitness center.

Palm Springs, California

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

Berlin

A saltwater thermal pool under a concrete dome near Berlin's Tempelhofer Feld, with sauna, steam room and occasional DJ nights.

Puelo, Los Lagos

Adults-only hot springs in Puelo with ten thermal pools, a sauna, steam room and individual herbal tubs, open daily with walk-in day passes.

New York City, New York

Thermal bath circuit and massages in a restored 1883 Tribeca textile factory, with a skylit tepidarium and candlelit thermal pools; reservation required.

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.

Milan, Lombardy

Adults-only day spa in a Liberty-style building near Milan's Parco Sempione, with thermal pools, saunas, steam room and a hydrotherapy circuit.

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.

Băile Felix, Bihor

Strand Apollo-Felix is a year-round thermal pool complex in Băile Felix, Romania, with indoor and outdoor pools open daily from 8am to 8pm.

Vichy, Auvergne-Rhône-Alpes

Adults-only thermal baths in Vichy using the town's mineral spring water, with a hydrotherapy circuit and thermal pool, booking required.

Leukerbad, Valais

Thermal baths inside a 19th-century hotel in Leukerbad, Valais, with mineral-rich pools open daily from 9am to 8pm.