Spas with hotel guests only

Palm Springs, California

A 16-room adults-only hotel in Desert Hot Springs with three natural mineral-water pools fed by a 350-foot geothermal well, plus a small on-site spa and

Rogaška Slatina, Savinjska

Wellness center at Grand Hotel Rogaška in Rogaška Slatina, Slovenia, with pools, saunas and fitness; day pass available by reservation.

Rotorua, Bay of Plenty

A lakefront resort spa in Holdens Bay, Rotorua, with day passes, jacuzzis, sauna and an onsite restaurant, open daily 8am-9pm.

Auckland

A family-run rainforest resort in the Waitakere Ranges near Auckland offering a day spa, private yoga and free hiking and biking trails.

Orlando, Florida

A hotel spa at Waldorf Astoria Orlando offering massages, facials and a Himalayan salt room, open daily 9am-5pm with day passes available.

Yalova

Historic Ottoman-era thermal baths in Yalova's Termal district, with day-pass access to pools and private bath cabins.

Houston, Texas

Hotel spa at Hotel ZaZa in Houston's Museum District, with massages, body treatments, infrared saunas and day-pass access to the pool lounge.

Miami, Florida

Hotel spa inside the InterContinental Miami, open daily with a day pass option, 11 treatments and a signature Raindrop Massage.

Tel Aviv, Tel Aviv District

Hotel spa inside Hotel Drisco Tel Aviv on Ben Yehuda Street, with rooftop baths, a Jacuzzi and couples' treatment rooms.

Vals, Grisons

Peter Zumthor's quartzite thermal baths in Vals, built into the mountain, open to day visitors as well as hotel guests.

Calistoga, California

A 1952 Calistoga hot springs resort with three mineral pools at 85, 95 and 104°F, mud baths, overnight rooms and a day-pass option.

Banff, Alberta

Luxury hotel spa inside Fairmont Banff Springs offering thermal pools, steam rooms and treatments, open daily with day passes for non-guests.

Ginzan Onsen, Yamagata

A riverside hotel spa in Ginzan Onsen with a thermal bathing pool, overnight stay and day-pass access for non-guests.

Brežice, Posavje

A large thermal water park in Brežice, Slovenia, with a year-round indoor pool riviera, an adults-only sauna zone, and seasonal outdoor slides.

Palm Springs, California

Boutique hotel spa in Desert Hot Springs with two natural mineral hot spring pools, day passes, and overnight rooms that include breakfast.

Four Corners, Florida

Hotel spa at Omni Orlando Resort ChampionsGate offering massages, facials and nail services, open to day-pass guests as well as hotel guests.

Las Vegas, Nevada

Adults-only hotel spa at Green Valley Ranch in Henderson, open daily 8am-8pm with day passes available to non-guests.

Palm Beach, Florida

Indoor-outdoor luxury spa at The Breakers resort in Palm Beach, open daily 9:30 AM to 6 PM, mainly for hotel guests and club members.

Soufrière

Resort spa at Ladera in Soufrière, St Lucia, set between the Pitons with day-pass access to pools, outdoor baths and treatments for couples.

Kurokawa Onsen, Kumamoto

Okunoyu is a ryokan onsen in Kurokawa Onsen, Kumamoto, with outdoor thermal baths open to day visitors and overnight guests, daily 8:30am–8:30pm.

Bad Ischl, Upper Austria

A salt-and-brine thermal bath complex in Bad Ischl with indoor/outdoor pools, a sauna world, and a rooftop wellness deck at the attached hotel.

San Diego, California

A rooftop hotel spa in San Diego's Gaslamp Quarter offering treatments and a 24/7 fitness center, open to hotel guests and day-pass visitors.

Băile Felix, Bihor

Strand Apollo-Felix is a year-round thermal pool complex in Băile Felix, Romania, with indoor and outdoor pools open daily from 8am to 8pm.

Asheville, North Carolina

Resort spa on an 85-acre Hendersonville farm near Asheville, with massage treatments in a converted horse barn, day passes, and a pool with sauna, steam and