Spas with thermal pool

Palm Springs, California

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.

Washington, D.C., District of Columbia

A multi-level day spa near DC with indoor and rooftop hydrotherapy pools, several sauna types, lounges, an a la carte spa menu and eateries.

Miami, Florida

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.

Tuscany

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

Tucson, Arizona

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.

Scottsdale, Arizona

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

Riviera Maya, Quintana Roo

Adults-only spa inside the all-inclusive Ocean Riviera Paradise resort in Playa del Carmen, with sauna, Turkish bath and four treatment options via day pass.

Palm Springs, California

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.

Tuscany

A five-star resort in the Tuscan countryside built around a natural thermal spring, with day passes from €39 for outdoor thermal pools, hydromassage circuits

Palm Springs, California

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.

Palm Springs, California

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

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.

Miami, Florida

A hotel spa in downtown Miami with a day pass covering sauna, steam, cold plunge and thermal pools, plus 13 treatments on the menu.

San Juan

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.

Napa Valley, California

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.

Phoenix, Arizona

Adults-only hotel wellness setup in downtown Phoenix with a heated pool, sauna and steam room, day passes available for $50.

Calistoga, California

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

Scottsdale, Arizona

A resort spa at JW Marriott Phoenix Desert Ridge with a thermal pool, relaxation lounge and on-site café, open to hotel guests and day-pass visitors.