Spas with groups

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

Carmel-by-the-Sea, California

Luxury hotel spa at the Pebble Beach resort in Carmel-by-the-Sea, open daily 9:30am-4pm with a juice bar, salon and day-pass access for non-guests.

Leukerbad, Valais

Thermal baths inside a 19th-century hotel in Leukerbad, Valais, with mineral-rich pools open daily from 9am to 8pm.

Solvang, California

A resort spa inside Alisal Ranch, a 10,500-acre luxury guest ranch in Santa Ynez Valley open only to overnight guests by reservation.

Asan, South Chungcheong

Hot springs resort spa in Asan with thermal pools, sauna and a relaxation lounge, open daily on a walk-in day-pass basis.

Băile Felix, Bihor

A thermal baths complex in Băile Felix with outdoor and indoor pools, open daily with walk-in access and no membership required.

Santa Cruz, California

A hotel spa on a 300-acre Santa Cruz hilltop with Monterey Bay views, outdoor baths and a relaxation lounge, open only to resort guests.

Pai, Mae Hong Son

A walk-in herbal sauna and cold-plunge spot in Pai with a restaurant and lounge attached, open daily 8am-10pm.

Crested Butte, Colorado

A hotel spa inside Elevation Hotel & Spa in Crested Butte, Colorado, open only to overnight guests staying at the slopeside property.

Catskills, New York

A resort spa in Mt Tremper, Catskills, offering treatments, a relaxation lounge and dining, open to both day-pass visitors and hotel guests.

Kapaau, Hawaii

An oceanfront eco-boutique hotel and wellness retreat on Hawaii Island's North Kohala coast, open to overnight guests only, not day visitors.

Thermopolis, Wyoming

Free public bathhouse in Thermopolis, Wyoming, with indoor and outdoor mineral soaking pools held at 104°F, open seven days a week.

Palm Springs, California

A 10-room mineral hot springs hotel in Desert Hot Springs near Palm Springs, offering day passes to its 120°F spring-fed pools, sauna and massage rooms.

Karjalohja, Uusimaa

Lakeside resort spa on Lohjanjärvi in Karjalohja, about an hour from Helsinki, with a day pass, thermal pool, salt room and restaurant.

Berkshires, Massachusetts

A lakeside resort in Egremont with a seasonal pool and sauna for overnight guests only; no day passes and no spa treatments on offer.

Moab, Utah

A downtown Moab hotel with a pool and two hot tubs reserved for overnight guests, plus an onsite coffee shop and bike storage.

Arima Onsen, Hyogo

Hotel spa in Arima Onsen with Arima's rare iron-rich "ginsen" waters, outdoor baths, sauna and jacuzzi, run as an all-inclusive overnight stay.

Miami, Florida

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.

Spa, Liège

Hotel spa in the town of Spa, Belgium, with a thermal pool, relaxation lounge and restaurant, open to day-pass visitors, not just hotel guests.

Catskills, New York

A Catskills retreat center with a Tibetan-style spa offering sauna, steam, pools and cold plunge, built around overnight stays and group programs.

Rancho Santa Fe, California

A Spanish Colonial-style luxury resort spa in Rancho Santa Fe near San Diego, open only to overnight guests, with 49 casitas and 45 acres of grounds.

Kyle, Texas

A 88-acre Hill Country resort near Kyle and Wimberley with overnight rooms, a garden spa, pool, hot tubs and day-pass access by reservation.

Park City, Utah

Serenity Spa is the treatment center inside Westgate Park City Resort, a ski-in villa resort with a year-round indoor/outdoor pool, sauna and steam room for