Spas with reservation required

Mauritius

Day spa in a Grand Baie residence offering massage, hammam and sauna, built around a signature foraha-oil massage and Dead Sea mineral facials.

Philadelphia, Pennsylvania

A reservation-only traditional Nordic sauna in North Philadelphia, open Wednesday through Monday and closed Tuesdays.

Vail, Colorado

A small massage and facial spa on the second floor of the Solaris building in Vail, offering nine treatments with no day pass.

Denver, Colorado

A medical spa in Thornton offering Japanese head spa treatments, body wraps, chemical peels and B12 shots, with sauna, steam room and pool access.

Orlando, Florida

Medical spa in Orlando offering facials, massage, body contouring and couples packages, with an on-site sauna, steam room and thermal pool.

New York City, New York

A below-street-level day spa in NoHo with thermal baths, a three-story indoor waterfall, sauna, steam room and cold plunge, plus massage and facial treatments.

Atlanta, Georgia

A reservation-only wellness center in Edgewood, Atlanta offering colon hydrotherapy, hyperbaric oxygen therapy, sauna and an oxygen bar for couples or solo

Gold Coast, Queensland

An overnight wellness retreat in Tallebudgera Valley with a cedar sauna, magnesium spa bath, ice bath and a 60-minute aromatherapy massage.

Boston, Massachusetts

A reservation-only day spa in Revere, near Boston, with sauna, couples suite and tropical rain vichy shower treatments.

Los Angeles, California

A women-focused Korean day spa in Pico-Union with steam, salt and ice rooms, open daily 9am to 9pm, with massage and facials open to men too.

Scottsdale, Arizona

A moderately priced day spa in South Scottsdale with lake-view suites, massage and facials, plus a dedicated couples treatment room.

Miami, Florida

A Peruvian-themed day spa inside the Victor Hotel on Ocean Drive, South Beach, with a hamam, steam room, sauna and a couples suite.

Oslo

Waterfront sauna spot on Aker Brygge with shared and private saunas, sea bathing, and sauna boat trips on the fjord.

Boston, Massachusetts

A Finnish kelo-log banya in Newton with sauna, steam room and cold plunge, alternating men's and women's days, day passes from $69.

Portland, Oregon

A membership-driven wellness club in downtown Portland with hot pools, sauna, steam room and cold plunge, plus massage, skincare and fitness classes.

Chicago, Illinois

Hotel spa on the lower level of the Fairmont Chicago, open to guests for massages, facials and a couples suite with an infinity-edge soaking tub.

Kraków, Lesser Poland

Day spa inside Hotel City SM in Kraków's quiet Łagiewniki-Borek Fałęcki district, offering massages, body and facial treatments, and couples packages.

Philadelphia, Pennsylvania

Northeast Philadelphia day spa on Castor Avenue focused on skin treatments, massage and Venus Legacy body contouring, with sauna, steam and a thermal pool.

Scottsdale, Arizona

Day spa in South Scottsdale offering massage, facials and body treatments, with walk-ins and couples appointments by reservation.

Indianapolis, Indiana

Day spa in Allisonville, Indianapolis with sauna, steam room, thermal pool and cold plunge, plus about 10 massage and facial treatments for solo visits or

Austin, Texas

Hotel spa at Omni Barton Creek with steam room, sauna, cold plunge and a rooftop pool overlooking Hill Country, open daily 9am-7pm.

Miami, Florida

An upscale day spa on Miracle Mile in Coral Gables with sauna, steam room and cold plunge, known for a $200 signature treatment and couples packages.

Austin, Texas

A head-spa studio inside IMAGE Studios in East Riverside, Austin, offering scalp detox, steam therapy, scalp massage and facial add-ons by appointment.

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.