Spas with hotel guests only

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 Florence's Four Seasons, with a walled garden pool, whirlpool, sauna, steam room and couples suite, open to day-pass guests.

A resort spa in Tucson's Starr Pass area with a saline lap pool, sauna and fitness center, plus signature treatments from $159 for hotel guests.

Adults-only hotel spa at The Scott in Scottsdale with six treatment rooms, sauna, steam and pools, plus day passes for non-guests.

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.

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

Adults-only hotel spa at the Parker Palm Springs with 15 private treatment rooms, couples suites and a $300 signature aloe treatment.

Sante Spa is the adults-only resort spa at the Riviera Palm Springs, with 18 treatment rooms, a Watsu pool, steam room and validated valet parking.

Hotel spa at The Phoenician in Scottsdale, open to guests 18+ who book a massage, facial, or body treatment, with sauna, steam room and a rooftop pool.

A 38,000-square-foot resort spa at JW Marriott Desert Springs in Palm Desert offers day passes, saunas, a saltwater lap pool and couples suites.

A beachfront resort on Anna Maria Island with a spa, sauna, steam room and pool, open to hotel guests, mainly geared toward couples.

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

Hotel spa at The Atlantic Resort on Fort Lauderdale Beach with sauna, steam room, cold plunge and thermal pool, for overnight guests only.

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

Hotel spa at the Catamaran Resort in Pacific Beach, San Diego, with a bay-view hot tub, pool and restaurant, open to hotel guests only.

Adults-only resort spa in Scottsdale with sauna, steam, cold plunge and thermal pools, open only to hotel guests.

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.

A rooftop pool, cabanas, fitness center and yoga room at this Houston hotel are open to non-guests via a $60 adults-only day pass.

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 deck in downtown Miami with sauna, steam room, cold plunge and thermal pools overlooking Biscayne Bay, day passes from $50.

A hotel spa inside Mission Pacific Beach Resort in Oceanside, open to guests, with a sauna, cooling mist shower and rooftop ocean views.

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

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.