Spas with thermal pool

Los Angeles, California

Four Seasons hotel spa in Beverly Hills with a steam room, rooftop pool, fitness center and eight treatments, open daily, day passes available.

Napa Valley, California

Adults-only hotel spa in Napa Valley with a co-ed thermal circuit of sauna, steam room and cold shower, open daily 10am–6pm; day passes available.

Palm Springs, California

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.

Boston, Massachusetts

A luxury hotel spa in Boston's Back Bay with a Crystal Steam Room, Vitality Pool and private couples suites, open to adults 18 and over.

Hudson Valley, New York

A historic resort spa at Mohonk Mountain House in the Shawangunk Mountains, with a heated mineral pool, steam room, sauna and day passes for non-hotel guests.

Napa Valley, California

Adults-only hotel spa in downtown Napa with thermal circuits, sauna, steam and cold plunge, plus massages, facials and medical aesthetics.

San Diego, California

Adults-only day and hotel spa in Rancho Bernardo with gardens, whirlpools, a steam room and an 18-treatment menu, open daily 9am-6pm.

Calistoga, California

A 20,000-square-foot resort spa in Calistoga with five geothermal pools, Calistoga mud treatments, and a day pass for non-hotel guests.

Chicago, Illinois

A hotel spa on Trump Chicago's mezzanine level offering day passes, 22 treatments, a heated pool, steam room, sauna and fitness club; minimum age 16.

Calistoga, California

A 20-treatment hotel day spa in Santa Rosa with an indoor caldarium plunge pool, eucalyptus steam rooms, and walk-in or reserved day passes for adults 18+.

Miami, Florida

Adults-only hotel spa on Belle Isle near South Beach with a hammam, sauna, ice room, infinity pool and a day pass option for non-guests.

Key West, Florida

A medical spa in Key West offering Morpheus8, injectables and body contouring, with a sauna, steam room and thermal pool on site by appointment only.

Detroit, Michigan

A downtown Detroit day spa with a thermal pool, sauna and steam room, offering about 70 treatments including a $240 couples massage.

Houston, Texas

A Houston day spa on E Airtex Dr with two locations, offering massage, facials and body treatments alongside a sauna, steam room, cold plunge and thermal pool.

Carmel, Indiana

A moderate-priced day spa in Carmel, Indiana with sauna, steam room and thermal pool, plus facials, massage and body contouring treatments.

The Colony, Texas

A day-soaking spa in The Colony with mineral pools at varying temperatures, seven saunas, cold plunges and a poolside café.

Park City, Utah

A reservation-only day spa in Sandy, Utah, built around scalp spa treatments, plus sauna, steam, cold plunge and thermal pools.

Miami, Florida

Medical spa in Miami's Edgewater doing Botox, fillers and facials, plus a sauna, steam room and thermal pool for aftercare.

Orlando, Florida

Adults-only hotel spa at the Hilton Orlando with a sauna, steam room, cold plunge and thermal pools, plus couples treatments and HydraFacials.

Scottsdale, Arizona

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

Sedona, Arizona

A Sedona day spa focused on deep tissue massage, fascia work and facials, with a sauna, steam room and thermal pool on site.

Osprey, Florida

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

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