Spas with thermal pool

San Francisco, California

Adults-only Russian bathhouse in San Francisco's India Basin with steam rooms, cold plunge, rooftop deck and a café, open daily except Tuesday.

Miami, Florida

A luxury day-pass wellness circuit inside Carillon Miami Wellness Resort, with sauna, steam, cold plunge and thermal pools in North Beach.

Tucson, Arizona

A luxury all-inclusive wellness resort in Tucson's Hidden Valley with four pools, a hydrotherapy circuit, cold plunges and over 200 spa treatments.

Temescal Valley, California

Adults-only hot springs resort in Temescal Valley with 19 outdoor mineral pools, red clay baths, and a cave-like grotto, open daily 9:30am-5pm.

Indianapolis, Indiana

Day spa in Allisonville, Indianapolis with sauna, steam room, thermal pool and cold plunge, plus about 10 massage and facial treatments for solo visits or

Park City, Utah

A 14-room hotel spa at Westgate Park City Resort with a waterfall, sauna, steam room and thermal pools, open daily 9:30am-6:30pm.

Scottsdale, Arizona

Hotel spa at the Inn at Eagle Mountain in Fountain Hills with sauna, steam room, pools and a $69 60-minute massage as its signature treatment.

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.

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.

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+.

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.

Miami, Florida

A hotel spa at Eden Roc Miami Beach in Mid-Beach with sauna, steam room, cold plunge and thermal circuits, open to resort guests only.