Spas with groups

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.

Park City, Utah

A sauna-and-cold-plunge day spa in Park City with memberships, private group buyouts, and reservation-only access.

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.

Los Angeles, California

A wellness retreat in Westlake's Wilshire corridor offering cold plunge, sauna and movement classes, built around group and community sessions.

Carmel-by-the-Sea, California

A hotel spa inside Carmel-by-the-Sea's Hyatt Regency Monterey property, with hydrotherapy, sauna and a relaxation lounge for guests and couples.

Naples, Florida

A hotel spa inside the Inn on Fifth in downtown Naples, open daily for massages, facials, nail services, sauna, steam room and lounge access.

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.

Prague

A beer-spa and wellness venue in Prague's Nové Město district offering beer-bath tubs, massages, and a saunarium, open daily from 11am to 11pm.

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

Miami, Florida

Hotel spa at the Fontainebleau Miami Beach resort on Collins Ave, open to hotel guests only.

Miami, Florida

A hotel spa inside the Four Seasons in Brickell, reserved for hotel guests, with rooftop pool and bay views as part of the stay.

Pai, Mae Hong Son

Affordable day spa near Pai's Wednesday Market open daily except Monday from 3pm to 9pm, with walk-in access and a sauna.

Park City, Utah

A hotel spa inside the ski-in/ski-out Pendry Park City resort in Canyons Village, open to guests of the property.

Hudson Valley, New York

Hotel spa inside a restored convent in Peekskill, overlooking the Hudson River, open only to overnight guests of The Abbey Inn.

Houston, Texas

Hotel spa inside Houston's only Forbes Five-Star tower in Uptown, limited to hotel guests, with a relaxation lounge and on-site dining.

Tulum, Quintana Roo

Beachfront resort in Tulum pairing overnight stays with spa treatments, yoga and fitness classes, open to hotel guests only.