Spas with upscale

French Riviera, Provence-Alpes-Côte d'Azur

Hotel spa inside Nice's Le Negresco with hammam, sauna and fitness center; outside guests must book a 90-minute treatment to use the wet areas.

Mexico City

Upscale adult-only day spa in Roma Norte with a six-treatment menu built around massage, skin care and one of the city's more elaborate hydrotherapy circuits.

Hobart, Tasmania

Upscale day spa in central Hobart with infrared sauna, magnesium spa, ice bath and in-house naturopathy, open daily except Mondays with walk-ins and day passes.

Denver, Colorado

A Littleton day spa centered on private suites with beer and wine baths, infrared sauna, zero-gravity massage and a self-pour taproom.

Santa Fe, New Mexico

A 77-acre hot springs resort outside Santa Fe with spring-fed thermal pools, day-pass soaking packages from $175, and overnight lodging.

Nashville, Tennessee

A full-service hotel spa on the fourth floor of Omni Nashville, downtown, offering massages, facials, salon services and a rooftop pool, open to non-guests via

Edinburgh, Scotland

One Spa is an adults-only day spa in Edinburgh's city centre with a rooftop Hydropool, thermal suite and day-pass access.

Shibu Onsen, Nagano

Reservation-only private hot spring and sauna suites at a Nagano brewery complex, built around a craft beer bathing plan for two to four guests.

Punta Cana, La Altagracia

Punta Cana Princess is an adults-only, all-inclusive resort spa in Bávaro, open to hotel guests only with free on-site parking.

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.

Houston, Texas

A Central Business District day spa with a rooftop pool, offering facials, massages and body treatments, open daily with walk-in access.

Lombok, West Nusa Tenggara

A hotel-guest-only wellness room at Rascals in Kuta, Lombok, with a traditional sauna, dual ice baths and a magnesium pool, open daily 8am–9:30pm.

Boston, Massachusetts

A Seaport social wellness club in Boston offering saunas, ice baths, IV therapy, red light and HBOT sessions, with reservations required and no membership

Nashville, Tennessee

A Midtown Nashville wellness studio built around cryotherapy, infrared sauna, red light therapy, IV drips and recovery treatments, run mostly through monthly

Scottsdale, Arizona

A hotel spa at JW Marriott Desert Ridge with sauna, steam rooms, a sanctuary pool, bistro and salon, open to day-pass guests as well as hotel guests.

Nashville, Tennessee

Day spa and medical spa on the third floor of The Westin Nashville downtown, with nine treatment rooms, a dry cedar sauna, steam showers and walk-in access to

Park City, Utah

Hotel spa in Canyons Village at the Grand Summit with sauna, steam room, three whirlpools and a 22-treatment menu including ski-recovery massages.

Jackson Hole, Wyoming

A hotel spa at Rustic Inn Creekside Resort in Jackson Hole with dry sauna, eucalyptus steam room, outdoor pool and hot tub, open to overnight guests only.

Sirmione, Lombardy

A lakeside thermal spa in Sirmione with indoor and outdoor pools fed by sulphurous spring water, a vascular circuit, saunas, and a day-pass option.

Scuol, Grisons

Hotel spa at the 4-star Belvedere in Scuol with indoor/outdoor pools, mineral and thermal water, sauna, steam bath and a day pass option.

Mauritius

Moroccan hammam and beauty salon in Grand Baie, Mauritius, offering steam rituals, scrubs and massages with sauna and hot tub, reservation only.

Jackson Hole, Wyoming

A Jackson Hole facility pairing physical therapy, acupuncture and massage with a climbing wall, salt room, infrared sauna and sound healing, open to day-pass

Vienna

Hotel spa in Vienna's Neubau district with a 20-metre indoor pool, two saunas, a steam room and day passes for non-guests.

Las Vegas, Nevada

Adults-only hotel spa inside Westgate Las Vegas offering massages, facials, salon services, sauna, steam room and a thermal pool, open daily 9am-6pm.