Spas with relaxation lounge

Asheville, North Carolina

Adults-only hotel spa in Asheville with a fiber-optic-starred lap pool, waterfall pools, saunas and an electronics-free policy; day passes are limited and

Miami, Florida

Hotel spa at The Ritz-Carlton Key Biscayne, Miami, with treatment suites, sauna, steam room and whirlpool, open to hotel guests 18 and up by appointment.

Galway, Connacht

Adults-only hotel spa in Galway with a thermal suite, hydro pool and sauna; day pass runs about €50 and reservations are required.

Chicago, Illinois

A hotel spa on Trump Chicago's mezzanine level offering day passes, 22 treatments, a heated pool, steam room, sauna and fitness club; minimum age 16.

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+.

Santa Fe, New Mexico

Small hotel day spa in downtown Santa Fe with a soaking pool, five treatment rooms and 25 services, open daily 8am-5pm by reservation.

Ho Chi Minh City

A Korean-style jjim jil bang in Ho Chi Minh City with six heated rooms, a Dead Sea mineral soaking pool, and massage, hair-wash and facial services.

Idaho City, Idaho

A reservation-only hot springs soak in Idaho City with private tubs, a steam room and a $30 day pass, open five days a week.

Miami, Florida

Adults-only hotel spa on Belle Isle near South Beach with a hammam, sauna, ice room, infinity pool and a day pass option for non-guests.

Philadelphia, Pennsylvania

Hotel spa in Center City Philadelphia with a heated indoor saltwater pool, fitness center and day-pass access for non-guests.

Aspen, Colorado

Adults-only hotel spa at Viewline Resort Snowmass with a $25 day pass, steam rooms, outdoor pool and whirlpool, reservations required.

Boston, Massachusetts

Hotel spa inside the Four Seasons One Dalton in Back Bay, with six treatments, a couples' suite and a 64-foot lap pool, open to hotel guests.

Sedona, Arizona

Adults-only resort spa in Sedona with outdoor hot tubs, steam rooms and a 30-treatment menu, open daily with walk-ins and day passes.

Portland, Oregon

A 21-and-up day spa in Portland's Irvington neighborhood built around vinotherapy, with wine-infused baths, massages and Caudalie facials.

Whistler, British Columbia

Hotel spa at the Westin in Whistler Village with 19 treatments, couples massage, and free access to the hotel's pools, sauna, steam room and gym.

Aix-les-Bains, Auvergne-Rhône-Alpes

Medical thermal baths in Aix-les-Bains treating respiratory and oral mucosal conditions with sulfur-rich water, mostly through prescribed multi-day cures.

Spa, Liège

Thermal baths in the town of Spa, Belgium, fed by natural mineral water, with saunas, hammams and separate textile and naturist relaxation areas.

San Pedro de Atacama, Antofagasta

A hotel spa inside the luxury Tierra Atacama lodge near San Pedro de Atacama, with indoor and infinity pools, sauna, steam room and treatment rooms, open only

Chicago, Illinois

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

Palm Springs, California

A 16-room adults-only hotel in Desert Hot Springs with three natural mineral-water pools fed by a 350-foot geothermal well, plus a small on-site spa and

Merano, Trentino-South Tyrol

An adults-only, guests-only longevity retreat and hotel spa in Merano with a medical-led wellness institute and private suite treatments.

Miami, Florida

Hotel spa at The Setai in Miami Beach with 7 ocean-view treatment rooms, 5 couples suites, saunas, steam and a cold plunge.

Rotorua, Bay of Plenty

A Rotorua day spa built around Ngāti Whakaue hot-springs traditions, centered on a seven-step geothermal Restorative Journey with lakeview thermal pools, mud

Taupo, Waikato

Adults-only geothermal hot springs in the Wairakei valley near Taupo, with three thermal pools fed by natural silica-rich mineral water, plus spa treatments