Spas with thermal pool

Aspen, Colorado

Adults-only hotel spa at The St. Regis Aspen with Thai-inspired massage, 111Skin facials, an AI robotic massage, and a day pass covering pool, cold plunge, and

Boston, Massachusetts

Hotel spa inside Raffles Boston pairing Guerlain facials and massages with a 65-foot lap pool, hot tub, sauna, steam room and three private treatment suites.

Lombok, West Nusa Tenggara

A hotel-guest-only wellness room at Rascals in Kuta, Lombok, with a traditional sauna, dual ice baths and a magnesium pool, open daily 8am–9:30pm.

Saratoga Springs, New York

Historic 1935 bathhouse in Saratoga Springs offering mineral water soaks and massages in original tubs, reservation only, moderate pricing.

Sirmione, Lombardy

A lakeside thermal spa in Sirmione with indoor and outdoor pools fed by sulphurous spring water, a vascular circuit, saunas, and a day-pass option.

Scuol, Grisons

Hotel spa at the 4-star Belvedere in Scuol with indoor/outdoor pools, mineral and thermal water, sauna, steam bath and a day pass option.

Palm Springs, California

Sante Spa is the adults-only resort spa at the Riviera Palm Springs, with 18 treatment rooms, a Watsu pool, steam room and validated valet parking.

Kyoto

Hotel spa in Kyoto's Higashiyama Ward with a day pass for pool, bathhouse, sauna and gym, plus treatment suites and couples options.

New York City, New York

Korean-style day spa in Edgewater, NJ, with saunas, thermal pools and an infinity pool, open daily 9am–9:30pm, day passes for walk-ins.

Auckland

Hotel day spa at Pullman Auckland CBD with a 25m heated pool, sauna, steam room, jacuzzi and gym plus massage and facial treatments.

Austin, Texas

Adults-only hotel spa at the Fairmont Austin with nine treatment rooms, a hydrotherapy circuit, sauna and cold plunge, open daily with day passes available.

Carmel-by-the-Sea, California

Resort spa at Carmel Valley Ranch with 12 treatment rooms, private terraces, a saltwater pool and infinity hot tub, open to adults by reservation.

Vail, Colorado

Hotel spa at the Westin Riverfront in Avon near Vail, with 14 treatment rooms, a saline lap pool, three infinity hot tubs and day passes for non-guests.

New York City, New York

A budget-friendly Korean-style bathhouse in Queens with indoor and outdoor hydrotherapy pools, saunas and a restaurant, open to walk-ins daily.

Dallas, Texas

Korean-style day spa in Carrollton with hydrotherapy pools, saunas and relaxation lounges, open daily 9am–9:30pm with walk-in day passes.

Piešťany, Trnava Region

Spa Irma on Piešťany's spa island offers historic mud and mirror thermal pools, a hydrotherapy circuit and a 60-treatment medical spa menu, adults only.

Park City, Utah

A 27-room resort spa at Montage Deer Valley in Park City, open to hotel guests with a pool, steam room, sauna and cold plunge.

Aix-les-Bains, Auvergne-Rhône-Alpes

An upscale day spa inside Hotel Le Riviera in Aix-les-Bains, with pools, saunas, a hammam and eight treatment rooms open to walk-ins.

Park City, Utah

Hotel spa at Pendry Park City with six treatment rooms, a rooftop pool, whirlpool and herbal steam room, open daily 8:30am–4:30pm.

Palm Springs, California

Adults-only hotel spa at Tommy Bahama Miramonte in Indian Wells with 15 treatments, eucalyptus steam rooms, a hydrotherapy jacuzzi and saltwater pool.

Napa Valley, California

Adults-only resort spa built into a wine cave in Napa, with a vineyard-view pool, sauna, steam room and hot tub; reservations required.

San Diego, California

Adults-only hotel spa at Kona Kai Resort on Shelter Island with six treatment rooms, a couples' suite and day-pass access for non-guests.

Sapporo, Hokkaido

Natural hot spring inside Sapporo's Jasmac Plaza Hotel in Susukino, open to day visitors and hotel guests alike, with sauna and a rest lounge.

Sárvár, Vas

A large thermal and wellness complex in Sárvár with indoor and outdoor medicinal pools, slides, a sauna world, fitness center and massage treatments.