Spas with upscale

Adults-only hot springs resort on Miracle Hill in Desert Hot Springs with private mineral tubs, a Finnish sauna, salt room and 35 spa treatments.

A beachfront resort spa in North Beach, Miami with cryotherapy, a floating salt bath, sauna, steam and a cold plunge, open to walk-ins and day-pass guests.

Hotel spa inside Dua Miami, Autograph Collection in Brickell, open daily 9am-6pm, with sauna, steam room, cold plunge and couples massage rooms.

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.

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.

A beachfront Waikiki hotel with a pool, fitness center and yoga sessions, open to guests staying at the OUTRIGGER Reef.

A 14-room hotel spa at Westgate Park City Resort with a waterfall, sauna, steam room and thermal pools, open daily 9:30am-6:30pm.

Hotel day spa atop the Archer in downtown Napa with a water deck, fitness studio access and treatment rooms; reservations required.

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

Hotel spa at Agua Caliente Rancho Mirage with day passes for the sauna, steam room, salt rooms and private spa pool.

Six-room hotel spa at Hacienda del Sol in Tucson, open daily 9-6, taking both resort guests and local walk-ins for massages, facials and body treatments.

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

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

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.

Adults-only hotel spa inside La Concha Resort in Condado, San Juan, offering couples massages and a small treatment menu for guests 18 and up.

Hotel spa and rooftop wellness deck in New Orleans' CBD with sauna, steam, cold plunge and thermal circuits, restricted to guests 21 and up.

Hotel spa inside The Highland Dallas in Lower Greenville, Dallas, with a sauna, steam room, outdoor pool and couples treatment rooms.

Adults-only hotel spa in Carlsbad with steam room, separate men's and women's lounges, and couples massage as its signature treatment.

Adults-only resort spa in Napa Valley with pools, sauna, steam and a fitness center, open to hotel guests and club members via day pass.

A hillside boutique hotel spa outside Sayulita with sauna, steam room, cold plunge and ocean-view pool, open on a day-pass basis.

An all-inclusive beachfront resort spa in Huatulco with a sauna, steam room and thermal pools, open only to hotel guests.

The spa at this all-inclusive Puerto Morelos resort offers hydrotherapy, massages and facials for hotel guests only.

A hotel spa at Eden Roc Miami Beach in Mid-Beach with sauna, steam room, cold plunge and thermal circuits, open to resort guests only.

Hotel spa on Shelter Island in San Diego with sauna, steam room, and pool, open to guests staying at Kona Kai Resort.