Spas with upscale

New York City, New York

Thermal bath circuit and massages in a restored 1883 Tribeca textile factory, with a skylit tepidarium and candlelit thermal pools; reservation required.

San Francisco, California

Hotel spa on the 8th floor of 1 Hotel San Francisco with rooftop stone soaking tubs and Bamford skincare treatments, open daily for day 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

Puyehue, Los Lagos

A forest resort spa in Puyehue, Chile, with volcanic thermal pools and outdoor baths, open only to hotel guests.

Leukerbad, Valais

A 30-room hotel in Leukerbad with a private thermal pool and sauna chalet, open to overnight guests only, overlooking the Gemmi massif.

Tucson, Arizona

Lakeside Spa at this 398-room desert resort in Tucson is open to hotel guests only, with two heated pools, a Jacuzzi and mountain views of Catalina range.

Bursa

Hotel spa in Bursa's Çekirge thermal district, guests-only access, with a thermal pool, hamam rituals and massage packages tied to multi-night stays.

San Diego, California

A resort spa on a 44-acre Mission Bay island in San Diego, open to hotel guests, with sauna, steam room and pool 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.

Scottsdale, Arizona

Hotel-guests-only spa at Scottsdale's Kimpton Miralina, with sauna, cold plunge and desert-inspired massages, mud wraps and facials.

Key West, Florida

Hotel day spa at Casa Marina in Key West offering ocean-view massages, facials and beachside yoga, walk-ins welcome.

Barcelona, Catalonia

Rooftop day spa at Casa Bonay hotel in Eixample with dry sauna, hammam, ice bath and a Japanese ofuro, booked by small-group circuit or free use.

Asheville, North Carolina

Resort spa on an 85-acre Hendersonville farm near Asheville, with massage treatments in a converted horse barn, day passes, and a pool with sauna, steam and

Boracay, Aklan

A hotel spa inside The Lind Boracay on Station 1 of White Beach, open daily 11am–11pm, reserved for hotel guests.

Santa Fe, New Mexico

Hotel spa at La Fonda on the Plaza in downtown Santa Fe, with a heated outdoor pool, hot tub, fitness center and relaxation lounge for guests of the hotel.

Vichy, Auvergne-Rhône-Alpes

Adults-only thermal baths in Vichy using the town's mineral spring water, with a hydrotherapy circuit and thermal pool, booking required.

Leukerbad, Valais

Thermal baths inside a 19th-century hotel in Leukerbad, Valais, with mineral-rich pools open daily from 9am to 8pm.

The Hamptons, New York

A membership-based wellness club in Southampton with a stadium-seating sauna, cold plunge pools, treatment suites and group classes.

Scottsdale, Arizona

Adults-only resort spa in Fountain Hills with sauna, steam room and outdoor pools, offering day passes and an amethyst facial as its signature treatment.

Portland, Oregon

Adults-only hotel and thermal springs on NE Alberta St in Portland, with vitality pools, a day-pass option, and spa treatments.

Las Vegas, Nevada

Upscale hotel spa and salon in Las Vegas with steam room, sauna, hot tub and a full menu of massage, facial and nail services, open 6am–8pm daily.

Jerusalem, Jerusalem District

An adults-only resort spa in the Judean Hills outside Jerusalem, with indoor and outdoor pools, a hammam and a day-pass option.

South Haven, Michigan

An adults-only glamping resort and pool club at South Haven Country Club with a day-pass spa area featuring a pool, sauna and relaxation lounge.