Spas with reservation required

San Diego, California

A Korean-style day spa on Convoy Street in Kearny Mesa offering sauna access, body scrubs and massage, open daily 8:30am to 9pm.

Rishikesh, Uttarakhand

An upscale riverside resort 18 km outside Rishikesh with an in-house spa, yoga studio and restaurant, open only to overnight guests by reservation.

Boston, Massachusetts

A Moroccan-style hammam on Route 1 in Peabody offering steam, sauna and exfoliation treatments for adults and couples, reservation only.

Catskills, New York

A small storefront in Catskill, NY offering whole-body cryotherapy, infrared sauna and red light therapy sessions, open most days except Tuesday and Wednesday.

Zanzibar

A moderate-priced day spa and hammam in Stone Town offering over 50 treatments, including Ayurvedic therapies and a sauna.

Carmel, Indiana

A no-frills contrast therapy studio in Carmel, Indiana, built around a 30-minute sauna-and-cold-plunge circuit for solo visitors.

Milwaukee, Wisconsin

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.

São Paulo

A holistic wellness center in São Paulo's Paraíso district running ayahuasca ceremonies, tarot sessions, massage therapy and weekend forest retreats with cabin

South Jordan, Utah

A day spa and wellness center in South Jordan, Utah, with a salt room, infrared sauna, cold plunge, float therapy and a yoga studio.

Antalya

A Turkish hammam and day spa in Konyaaltı, Antalya, offering steam baths, scrub-and-foam treatments, Doctor Fish, and massage therapy.

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.

Nashville, Tennessee

Float Horizen is a day spa in Nashville's East End offering sensory-deprivation float tanks, infrared sauna, massage and sound meditation sessions.

Tucson, Arizona

Day spa in Tucson's La Encantada shopping center with a thermal circuit of sauna, steam room, cold plunge and soaking pools.

Colorado Springs, Colorado

An adults-only medical day spa in Colorado Springs offering constitutional hydrotherapy, infrared sauna and homeopathy by appointment.

Miami, Florida

A beer-bath spa in Little Haiti where you soak in a cedar tub infused with hop ingredients and sip a cold beer on tap.

Scottsdale, Arizona

Hammam-inspired hotel spa at Omni Scottsdale Resort & Spa at Montelucia in Paradise Valley, with private suites and massage, facial and body treatments for

Vail, Colorado

A Vail day spa offering customized massages and facials plus a recovery room with infrared sauna, cold plunge and yoga mats.

San Diego, California

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

Philadelphia, Pennsylvania

A medical spa in Philadelphia's Northern Liberties/Fishtown area offering facials, laser treatments, injectables, massage and bridal prep packages.

Richmond, Virginia

Day spa in Richmond's West End with massage, organic facials, HydraFacial, infrared sauna and herbal bath soaks; walk-ins welcome, reservations recommended.

Portland, Oregon

Day spa and natural medicine clinic in NW Portland's Slabtown with sauna, hydrotherapy, massage, acupuncture and a vegan café on site.

Santa Barbara, California

A State Street halotherapy spa built around a large underground crystal salt cave, with massage, facials and a relaxation lounge.

Kandy, Central Province

An adults-only Ayurvedic retreat in the hills above Kandy, Sri Lanka, with overnight stays, yoga and a restaurant, but no day-pass access.

Punta Cana, La Altagracia

Upscale day spa in Punta Cana offering massages, facials, a thermal pool and ocean-view relaxation lounges, open daily 9am-7pm.