Spas with moderate

Carson, Washington

A clothing-optional, adults-only mineral hot springs bathhouse in Carson, Washington, with a $12 day pass and a $30 bath-and-wrap treatment.

San Diego, California

Hotel spa at the Catamaran Resort in Pacific Beach, San Diego, with a bay-view hot tub, pool and restaurant, open to hotel guests only.

Incheon

Cimer is a Korean spa in Unseo-dong, Jung-gu, Incheon, open daily 10am–9pm with a pool and walk-in access.

Many, Louisiana

Hotel spa at Cypress Bend Resort on Toledo Bend Lake in Many, Louisiana, with a sauna, hot tub, and heated indoor and outdoor pools.

San Diego, California

Hotel wellness facilities at the DoubleTree Del Mar in Carmel Valley, San Diego, with a sauna, steam room, outdoor pool and fitness center for hotel guests.

Granada, Andalusia

An Arab-style bathhouse in Granada's Centro district with thermal pools and a relaxation lounge, open daily 10am–10:30pm, adults only.

Riviera Maya, Quintana Roo

Resort spa at the Fiesta Americana Cozumel with sauna, steam room, cold plunge and couples treatments, open to hotel guests only.

Mývatn, Northeastern Region

A 92-room hotel at Lake Mývatn with an in-house sauna for overnight guests only; no day-pass access.

Lake Tahoe, California

A resort spa inside Granlibakken's mountain lodging complex near Tahoe City, open to hotel guests with a pool, hot tub and yoga space on site.

Termas de Río Hondo, Santiago del Estero

An all-inclusive family resort in Termas de Río Hondo with thermal pools, a spa and buffet dining, open to hotel guests only.

San Diego, California

A hotel spa at the Handlery Hotel in Mission Valley, San Diego, with sauna, steam room, cold plunge and thermal pools for guests.

Calistoga, California

A clothing-optional hot springs retreat outside Calistoga with eight mineral pools, spa bodywork, and day-pass, camping, and lodging options.

Los Baños, Laguna

A natural spring resort near Mount Makiling in Calauan, Laguna, with outdoor pools, forest trails, and day passes offered every day of the week.

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 Francisco, California

A Japantown bathhouse open for 50+ years, with a Japanese-style thermal pool and relaxation lounge, reservation required, adults only.

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.

San Miguel de Allende, Guanajuato

A Saturday-only hot springs day spa near San Miguel de Allende with outdoor thermal pools and walk-in access.

Palm Springs, California

Resort spa in Desert Hot Springs with mineral thermal pools, open to day-pass visitors and hotel guests, geared toward couples and families.

San Francisco, California

An adults-only bathhouse in San Francisco's Tenderloin with a thermal pool and an on-site restaurant, open daily except Tuesdays.

Pamukkale, Denizli

A 315-room thermal resort in Karahayıt near Pamukkale with its own thermal pools, pine-shaded gardens and on-site dining, open to hotel guests only.

Vienna

A day-pass bathhouse on Handelskai in Leopoldstadt with a sauna and thermal pool, open daily 10am–10pm.

Nashville, Tennessee

A hotel wellness area at Sheraton Music City near Nashville airport, open to guests 21 and up, with sauna, steam room, pools and a whirlpool.

Reykjavik, Capital Region

An oceanfront thermal bath in Kópavogur near Reykjavik, open daily with outdoor pools facing the sea and walk-in day passes.