Spas with thermal pool

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.

Seattle, Washington

A reservation-only social wellness sauna spa in Renton (serving the Seattle area) with a thermal pool, cold plunge, sauna and steam room, day passes from $75.

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.

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.

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.

Atami, Shizuoka

Hotel spa inside Fufu Atami using Sisley's plant-based treatments, with sauna, steam and thermal pool access for adults only.

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.

Tucson, Arizona

Adults-only hotel spa at El Conquistador Tucson with a salt therapy lounge, heated outdoor pool and mountain views, day passes available to hotel guests.

Quebec City, Quebec

A riverside Nordic spa in Old Quebec with an infinity pool, salt-water floating bath and thermal baths along the St. Lawrence, open daily 9am-10pm.

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.

Las Vegas, Nevada

A day spa inside Tuscany Suites & Casino in Las Vegas offering massage, facials and body treatments alongside sauna, steam and cold plunge access.

Taupo, Waikato

Adults-only geothermal pool complex in Taupo with five heated pools and a cold plunge, open daily noon to 9pm, no time limit.

Tuscany

A five-star resort in the Tuscan countryside built around a natural thermal spring, with day passes from €39 for outdoor thermal pools, hydromassage circuits

Hot Springs, Arkansas

Historic 1924 thermal bathhouse inside the Arlington Hotel in Hot Springs, offering mineral baths, sauna and massage, with walk-ins welcome.

Queenstown, Otago

Adults-only bathhouse in central Queenstown with heated, ambient and cold pools, sauna and steam room, day pass $99.

Seattle, Washington

A quiet, clothing-optional day spa in Greenwood with soaking pools, saunas and a steam room, women-owned and open to all genders on Wednesdays.

Taos, New Mexico

Hotel day spa at El Monte Sagrado in Taos with a hydrotherapy circuit, saltwater pool and treatment rooms, open daily, day passes available.