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.

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 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.

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.

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.

An outdoor heated pool and jacuzzi at this Aloft hotel in Dublin, California, available to guests staying 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.

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.

A hotel wellness area at Sheraton Music City near Nashville airport, open to guests 21 and up, with sauna, steam room, pools and a whirlpool.

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 21-and-over hotel in Johnson City, NY, with a sauna, hot tub and fitness center for guests staying at the property.

A 25-room Sonoma hotel in Forestville with a spa barn offering sauna, steam and pools, mainly for overnight guests.

A hotel spa inside the Four Seasons Resort Chiang Mai in Mae Rim, with sauna, steam room, cold plunge and thermal pools set among rice paddies, open to resort

A hotel-guests-only desert resort in Desert Hot Springs built around natural mineral hot spring pools, with spa treatments and overnight stays.