Spas with upscale

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.

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

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.

Hudson Valley, New York

Hotel spa at a small Hudson Valley inn on 75 riverside acres in Milton, NY, open to overnight guests by reservation while the spa undergoes renewal.

Portland, Oregon

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

San Francisco, California

Adults-only hotel spa in Sausalito, California, offering day passes alongside yoga and a restaurant on site.

Santa Cruz, California

A hotel spa on a 300-acre Santa Cruz hilltop with Monterey Bay views, outdoor baths and a relaxation lounge, open only to resort guests.

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.

Tbilisi

A hotel-guests-only private spa in Tbilisi's Chugureti district with a Finnish sauna, Turkish steam room and jacuzzi booked for one party at a time.

Crested Butte, Colorado

A hotel spa inside Elevation Hotel & Spa in Crested Butte, Colorado, open only to overnight guests staying at the slopeside property.

Catskills, New York

A resort spa in Mt Tremper, Catskills, offering treatments, a relaxation lounge and dining, open to both day-pass visitors and hotel guests.

Encinitas, California

Adults-only day spa in Leucadia, Encinitas, about a mile from the beach, with private suites, a relaxation lounge and movement classes.

Bad Ragaz, St. Gallen

Hotel resort spa in Bad Ragaz built around the valley's 36.5°C thermal water, with saunas, pools and treatments open to overnight guests.

Riviera Maya, Quintana Roo

Beachfront all-inclusive resort in Playa del Carmen with a hydrothermal circuit spa available to hotel guests for an extra charge.

Cancún, Quintana Roo

A boutique hotel near Cancún airport with a small wellness wing — pool, jacuzzi, sauna, steam room and temazcal — open to day-pass visitors.

Opatija, Primorje-Gorski Kotar

Hotel spa inside Opatija's Hotel Miramar, open only to guests staying in its 108 mostly sea-view rooms.