Spas with upscale

Sonoma, California

A boutique day spa in downtown Sonoma centered on infrared sauna and cold plunge drop-ins, plus massage, red light and PEMF therapy.

Auckland

Hotel day spa at Pullman Auckland CBD with a 25m heated pool, sauna, steam room, jacuzzi and gym plus massage and facial treatments.

Austin, Texas

Adults-only hotel spa at the Fairmont Austin with nine treatment rooms, a hydrotherapy circuit, sauna and cold plunge, open daily with day passes available.

Dallas, Texas

Hotel spa inside The Adolphus in downtown Dallas, with six treatment rooms, a couple's suite and a 22-item menu of massages, facials and body treatments.

Vail, Colorado

Hotel spa at the Westin Riverfront in Avon near Vail, with 14 treatment rooms, a saline lap pool, three infinity hot tubs and day passes for non-guests.

Las Vegas, Nevada

Spa Aquae is JW Marriott Las Vegas Resort & Spa's day spa in Summerlin, with 18 treatments, couples massages and a steam room, open daily 8am-7pm.

Palm Springs, California

Hotel spa at the Renaissance Esmeralda in Indian Wells offering desert-inspired treatments, a recovery lounge, steam rooms and day passes, adults only.

Boca Raton, Florida

Hotel spa at The Boca Raton with 44 treatment rooms, a spa pool and waterfall whirlpools, open to resort guests, club members and day-pass visitors by

Napa Valley, California

Adults-only resort spa built into a wine cave in Napa, with a vineyard-view pool, sauna, steam room and hot tub; reservations required.

Austin, Texas

Hotel spa at Hotel Viata in West Lake Hills with treatment rooms, a couples suite, pool, sauna, steam room and a day-pass option for amenity access.

Orlando, Florida

Upscale day spa at Bella Collina private club near Orlando, open Tuesday–Sunday by appointment, with massages, facials and couples suites.

San Diego, California

Hotel spa at the historic Hotel del Coronado with an ocean-view pool, 20 treatments, and a seaweed-based signature Ocean Essence Ritual.

San Diego, California

Adults-only hotel spa at Kona Kai Resort on Shelter Island with six treatment rooms, a couples' suite and day-pass access for non-guests.

Quebec City, Quebec

A riverside Nordic spa in Old Quebec with an infinity pool, salt-water floating bath and thermal baths along the St. Lawrence, open daily 9am-10pm.

Miami, Florida

A 12,000-square-foot hotel spa at Coral Gables' Biltmore, with eucalyptus steam rooms, Himalayan salt saunas and a couples suite; adults-only, reservation

Charleston, South Carolina

Hotel spa in Ansonborough with cypress-clad treatment rooms, a signature citrus facial, and a second-floor fitness studio; walk-ins welcome.

Santa Ynez, California

Adults-only resort spa inside Chumash Casino Resort in Santa Ynez with 21 treatments, a mineral pool, cold plunge and couple's suites.

Calistoga, California

Hotel spa in downtown Healdsburg with a garden patio, jacuzzi and pool access, open daily 9am-5pm for guests and day visitors.

Scottsdale, Arizona

Resort spa at Camelback Inn in Scottsdale with 20 treatment rooms, a thermal circuit and day-pass access open to non-guests.

Napa Valley, California

Adults-only hotel spa in Napa Valley with a co-ed thermal circuit of sauna, steam room and cold shower, open daily 10am–6pm; day passes available.

Hunter Valley, New South Wales

Large day spa at Chateau Elan in Hunter Valley with 17 treatment rooms, a float tank, outdoor mineral spas and couples' treatments; day passes and walk-ins

Las Vegas, Nevada

An adults-only hotel spa inside Encore Las Vegas with whirlpool, sauna and steam room, open daily for treatments and day passes, walk-ins welcome.

San Diego, California

Adults-only hotel spa in Carmel Valley with a hydrotherapy circuit, two fireplace lounges, and a $100 day pass covering pools and fitness facilities.

Austin, Texas

A hotel spa in downtown Austin with six treatments, a salt-wall relaxation lounge, eucalyptus steam rooms and a fitness center, open daily by reservation.