Spas with upscale

Palm Springs, California

Downtown Palm Springs day spa built around a natural hot mineral spring, with private mineral baths, sauna, steam room and massage.

Sonoma, California

Hotel spa at The Lodge at Sonoma with an outdoor terrace, soaking pool, plunge pool and barrel sauna, open daily 9am-5pm, adults-only, reservation required.

Carmel-by-the-Sea, California

A hotel spa at Quail Lodge and Golf Club in Carmel-by-the-Sea with a steam room, three private fitness cabanas and a heated outdoor pool, limited to hotel

Portland, Oregon

Adults-only day spa in Portland's Hosford-Abernethy neighborhood offering facial treatments by appointment in private suites, no walk-ins or day passes.

Park City, Utah

A ten-treatment-room spa inside the private Promontory Club in Park City, with a full hydrotherapy circuit of steam, sauna and cold plunge.

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.

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.

Miami, Florida

A Brickell medical spa running 18 categories of non-invasive aesthetic treatments, including Botox, fillers and a signature facial, weekdays only.

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.

Scottsdale, Arizona

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

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

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.

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.

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.

San Antonio, Texas

Full-service resort spa at the Hyatt Regency Hill Country in San Antonio, with thermal circuits, cold plunge and day passes open to non-guests.

Riviera Maya, Quintana Roo

A resort spa inside the Iberostar Waves Tucán in Playacar offering sauna, Turkish bath and jet-pool treatments, open to day-pass visitors 16 and up.

Miami, Florida

mySpa at InterContinental Miami is a hotel spa in Downtown Miami offering a sauna, steam room, pools and a cold plunge, open to hotel guests only.

Jekyll Island, Georgia

Hotel spa at Jekyll Island Club Resort offers outdoor baths and a pool with ocean views, open only to resort guests.