Spas with outdoor baths

Baden-Baden, Baden-Württemberg

Modern thermal baths in Baden-Baden with indoor-outdoor pools and a Roman-style sauna garden, open daily 8am–10pm, day pass €40.

Jackson Hole, Wyoming

A day spa next to the Trailborn hotel in Jackson Hole with an outdoor pool deck, salt lounge and day passes for walk-in soaks or treatments.

Reykjavik, Capital Region

Eight oceanfront geothermal pools in Hvalfjörður, 45 minutes from Reykjavík, plus steam baths, a bistro and guest houses for rent.

Oslo

Waterfront sauna spot on Aker Brygge with shared and private saunas, sea bathing, and sauna boat trips on the fjord.

Saratoga Springs, New York

A floating Nordic-style sauna moored on Saratoga Lake, with a 15-person cabin, roof terrace and lake plunge, open daily except Monday.

St. Moritz, Grisons

An indoor-outdoor pool and spa complex in St. Moritz-Bad with four pools, three slides, a sauna zone, fitness center and bike/Nordic hub under one roof.

Gothenburg, Västra Götaland County

A rooftop pool club and spa spanning two floors of the Jacy'z hotel in Gothenburg, with heated pools, sauna, steam room and a bar-restaurant, open for day

Shibu Onsen, Nagano

Reservation-only private hot spring and sauna suites at a Nagano brewery complex, built around a craft beer bathing plan for two to four guests.

Napa Valley, California

Adults-only resort spa built into a wine cave in Napa, with a vineyard-view pool, sauna, steam room and hot tub; reservations required.

Arima Onsen, Hyogo

A moderately priced onsen bathhouse in Arima Onsen, Kobe, with a forest sauna, a large outdoor bath, yoga and an award-recognized restaurant.

Wanaka, Otago

A lakefront wood-fired sauna at The Outlet in Wānaka running guided or self-guided group sessions with cold dips in the lake between rounds.

Los Angeles, California

Four Seasons hotel spa in Beverly Hills with a steam room, rooftop pool, fitness center and eight treatments, open daily, day passes available.

Leukerbad, Valais

A 30-room hotel in Leukerbad with a private thermal pool and sauna chalet, open to overnight guests only, overlooking the Gemmi massif.

Transylvania County, North Carolina

All-inclusive multi-night wellness retreat in Pisgah Forest, NC, combining fitness classes, spa treatments, guided hikes and farm-to-table meals in private

Barcelona, Catalonia

Rooftop day spa at Casa Bonay hotel in Eixample with dry sauna, hammam, ice bath and a Japanese ofuro, booked by small-group circuit or free use.

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.

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.