Spas with reservation required

Aachen, North Rhine-Westphalia

A suite hotel in central Aachen where each private room has its own jacuzzi and sauna, booked by the night rather than a day pass.

Boston, Massachusetts

Day spa in East Boston offering massages, facials, body care and a hydrotherapy circuit, open daily except Sunday with walk-ins welcome.

Pagosa Springs, Colorado

A mobile container-trailer spa in Pagosa Springs offering infrared sauna and cold plunge contrast therapy, adults only, by reservation.

Dallas, Texas

A moderate-priced day spa inside The Crescent complex in Oak Lawn, Dallas, with a sauna and both walk-in and reservation options.

Los Angeles, California

A medical spa in Silver Lake, Los Angeles offering body contouring, massage, hair removal and skin treatments in private suites, open daily 9am to 10pm.

Bad Ragaz, St. Gallen

A resort thermal spa in Bad Ragaz with indoor and outdoor thermal pools and sauna, open daily 7:30am–8pm, reservation required for day passes.

Palm Beach, Florida

A budget-friendly day spa in Palm Beach Gardens offering massage, facials and a private hot-cold contrast therapy suite, with walk-in access.

Chicago, Illinois

A Gold Coast medical and day spa combining massage, facials, laser and injectables with a robe-and-locker relaxation lounge, open daily except Tuesday and

Tepoztlán, Morelos

A day spa and temazcal (traditional Mexican sweat lodge) in Tepoztlán, Morelos, open Wednesday through Sunday with reservations suggested.

Kyoto

Hotel spa on the 2nd floor of Dhawa Yura Kyoto in Higashiyama, offering private-suite treatments by Banyan Tree Academy-trained therapists.

Park City, Utah

Hotel spa at Mayflower Mountain near Deer Valley with massages, facials, a sauna, relaxation lounge and couples treatments; reservations required.

Berkshires, Massachusetts

A Great Barrington wellness studio focused on detox therapies like colon hydrotherapy, infrared sauna and liver flushes, by appointment only.

Tucson, Arizona

Adults-only day spa in Tucson's Triangle area offering lymphatic facials, dermaplaning and a hydrotherapy circuit; reservations required.

Hudson Valley, New York

An outdoor spa on the Hudson River in Kingston, NY, with two waterfront barrel saunas and garden massage cabins, reservation required.

Arima Onsen, Hyogo

Hotel spa in Arima Onsen with Arima's rare iron-rich "ginsen" waters, outdoor baths, sauna and jacuzzi, run as an all-inclusive overnight stay.

New York City, New York

A small Japanese-style bathhouse near Union Square with sauna, hot-tub onsen, cold plunge and a recovery lounge, open by reservation only.

Prague

A beer-spa and wellness venue in Prague's Nové Město district offering beer-bath tubs, massages, and a saunarium, open daily from 11am to 11pm.

Taos, New Mexico

A boutique skin and body studio in Taos offering facials, lymphatic massage, Endermologie and head spa treatments by appointment.

Catskills, New York

A Catskills retreat center with a Tibetan-style spa offering sauna, steam, pools and cold plunge, built around overnight stays and group programs.

Sedona, Arizona

A 23-casita destination spa resort inside Sedona's Boynton Canyon, open to overnight hotel guests 16 and older for multi-day wellness journeys.

Kyle, Texas

A 88-acre Hill Country resort near Kyle and Wimberley with overnight rooms, a garden spa, pool, hot tubs and day-pass access by reservation.

Seattle, Washington

A downtown Seattle yoga studio with heated and unheated vinyasa, sculpt and hatha classes, plus a sauna, steam room and pools for after class.

Asheville, North Carolina

An overnight-stay forest retreat near Fairview with private cedar hot tubs and a shared sauna pavilion session, not a drop-in day spa.

Penang

An adults-only villa resort spa near Kepala Batas, Penang, with 18 private villas, spa treatments and plant-based dining; reservation required.