Spas with solo travelers

Denver, Colorado

A Denver day spa in Speer built around the Vietnamese Red Dao herbal bath, with infrared sauna, salt chamber and foot baths, open daily 10am-6pm.

Seattle, Washington

An adults-only wellness studio near Green Lake with private infrared sauna suites, therapeutic massage and red light therapy by reservation.

Sedona, Arizona

A moderately priced day spa in Sedona with outdoor gardens, a hot tub and fountains, known for its Prickly Pear Pomegranate body treatment.

Asheville, North Carolina

A Japanese-inspired destination spa on a mountainside outside downtown Asheville, built around private outdoor salt hydrotherapy tubs and massage.

Charleston, South Carolina

A wellness studio in Charleston's Cannonborough Elliotborough built around a 400 sq ft Himalayan salt room, plus float therapy, infrared saunas and body work.

Santa Barbara, California

A downtown Santa Barbara day spa built around a private infrared sauna, salt room, cold plunge and a sound-and-light meditation pod, booked by appointment.

Washington, D.C., District of Columbia

Downtown K Street day spa in DC offering massage, facials, infrared sauna and a salt therapy lounge, open daily 10am-8pm with day passes available.

Nashville, Tennessee

A Berry Hill day spa in Nashville offering massage, facials, body treatments and a sauna pod/salt room, open Tuesday through Saturday.

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.

Asheville, North Carolina

A trauma-informed day spa in Asheville's Haw Creek neighborhood with saltwater floatation tanks, massage, infrared sauna and facials; walk-ins welcome.

Nashville, Tennessee

A Germantown contrast therapy studio with private suites pairing infrared sauna, cold plunge and a vitamin-c shower; day pass is $70.

Charleston, South Carolina

Contrast therapy studio in Mt Pleasant offering private 60-minute sessions with infrared sauna, cold plunge and vitamin-c shower; day pass $60.

Palm Beach, Florida

A Palm Beach Gardens studio offering 60-minute private-suite sessions combining infrared sauna, cold plunge and vitamin-c shower.

Charleston, South Carolina

Private contrast-therapy suites with infrared sauna, cold plunge and vitamin C shower in West Ashley, Charleston, by reservation.

Ibusuki, Kagoshima

Oceanfront outdoor onsen in Ibusuki where the two gender-assigned baths swap daily, with views of Mount Kaimon, the East China Sea, and Take-yama.

Los Angeles, California

A Silver Lake day spa with 20 treatments, Thai massage, acupuncture and a salt-infused infrared sauna, open daily 10am-9pm.

Calistoga, California

Hotel spa in downtown Healdsburg with a garden patio, jacuzzi and pool access, open daily 9am-5pm for guests and day visitors.

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.

Houston, Texas

A Four Seasons hotel spa in downtown Houston with three treatment rooms, a couples' suite and rooftop pool access, open to day-pass guests.

Milan, Lombardy

A luxury hotel spa inside Four Seasons Hotel Milano with a 14-metre pool under a vaulted ceiling, sauna, gym and private suites for couples' treatments.

Vail, Colorado

A day spa and recovery club in downtown Vail with hot tub, sauna, steam room, cold plunge and salt lounge, plus day passes and fitness access.

Chicago, Illinois

A 5th-floor day spa inside the Palmer House Hilton in the Loop, built around a hydrotherapy circuit, Vichy shower treatments and a facial called Glow Revival.

Las Vegas, Nevada

Hotel spa on the Palms casino level in Las Vegas with steam rooms, saunas, a seasonal pool and 32 treatments including massage, facials and body work.

San Diego, California

Resort spa on Mission Bay offering massages, facials and body treatments, with walk-ins welcome and a gym and yoga classes on-site.