Spas with groups

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.

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.

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.

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.

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.

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.