Spas with adults only

A moderately priced day spa in Chicago's Lakeview neighborhood focused on Chinese-style head and scalp treatments, open to adults 16 and up.

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

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

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

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

A St. Paul wellness studio in Macalester-Groveland offering infrared sauna, float tanks, salt therapy and cold plunge by reservation, adults-only, day-pass

A moderate-priced holistic wellness center in West Colorado Springs offering dry salt therapy, massage, yoga and occasional sound-healing or cacao ceremonies.

Adult-focused day spa in North Tampa offering facials, massage, waxing, infrared sauna and salt therapy, open daily with walk-ins welcome.

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

Day spa in Steiner Ranch, Austin, offering sauna, steam room, thermal pools, cold plunge and a signature scalp treatment for adults, open Monday through

A halotherapy day spa in West Elkridge, near Baltimore, built around a salt cave, massage rooms and a yoga studio, aimed at solo adult visitors.

Downtown Palm Springs day spa built around a natural hot mineral spring, with private mineral baths, sauna, steam room and massage.

East Town Spa in Milwaukee's Juneau Town combines a full-service salon and med spa with a thermal circuit of sauna, steam, pools and cold plunge.

An adults-only wellness retreat on Ubud's Ayung River offering multi-day healing programmes, thermal circuits and plant-based cuisine by reservation only.

A Clairemont wellness studio in San Diego pairing acupuncture and bodywork with an infrared sauna and a Himalayan salt room for classes.

All-inclusive multi-night wellness retreat in Pisgah Forest, NC, combining fitness classes, spa treatments, guided hikes and farm-to-table meals in private

A moderate-priced day spa in Minnetonka with a sauna, steam room, thermal pool and cold plunge, set up for couples and adults-only visits.

A single-room salt cave in a Carmichael strip mall offering 45-minute salt therapy sessions for relaxation and respiratory relief.

Adults-only resort spa in Fountain Hills with sauna, steam room and outdoor pools, offering day passes and an amethyst facial as its signature treatment.

Adults-only resort spa in Scottsdale with sauna, steam, cold plunge and thermal pools, open only to hotel guests.

A 21-and-over hotel spa in San Diego's Gaslamp Quarter with sauna, steam room, cold plunge and thermal pools, open to hotel guests only.

A North Royalton day spa built around a salt room and sauna, with adults-only halotherapy sessions on a walk-in or reserved basis.

A rooftop pool, cabanas, fitness center and yoga room at this Houston hotel are open to non-guests via a $60 adults-only day pass.

A hotel spa in downtown Miami with a day pass covering sauna, steam, cold plunge and thermal pools, plus 13 treatments on the menu.