Spas with hotel guests only

Ainsworth, British Columbia

A lakeside hot springs resort in British Columbia's Kootenays with public thermal pools, a spa, restaurant and overnight rooms, closed Tuesdays.

Bagno Vignoni, Tuscany

Hotel spa in a 15th-century Bagno Vignoni palazzo with a thermal pool fed by the village's natural hot springs, open to day visitors.

Palm Springs, California

Adults-only hot springs resort on Miracle Hill in Desert Hot Springs with private mineral tubs, a Finnish sauna, salt room and 35 spa treatments.

Calistoga, California

A moderate-priced resort spa in Calistoga with geothermal mineral pools, open daily 9am-5pm and offering day passes to the public.

Hot Springs, Arkansas

A nine-suite boutique hotel on Bathhouse Row with in-room soaking tubs fed by hot spring mineral water, open only to overnight guests.

Bursa

A historic thermal bathhouse and small hotel in Bursa's Kükürtlü district, with separate men's and women's hamams, day passes, and overnight stays.

Santa Fe, New Mexico

A 77-acre hot springs resort outside Santa Fe with spring-fed thermal pools, day-pass soaking packages from $175, and overnight lodging.

Archena, Murcia

Thermal spa resort in Archena, Murcia, with a 3,000m² thermal circuit, outdoor baths and a day pass from €23.

Tuscany

A five-star resort in the Tuscan countryside built around a natural thermal spring, with day passes from €39 for outdoor thermal pools, hydromassage circuits

Rogaška Slatina, Savinjska

Wellness center at Grand Hotel Rogaška in Rogaška Slatina, Slovenia, with pools, saunas and fitness; day pass available by reservation.

Calistoga, California

A 1952 Calistoga hot springs resort with three mineral pools at 85, 95 and 104°F, mud baths, overnight rooms and a day-pass option.

Palm Springs, California

Boutique hotel spa in Desert Hot Springs with two natural mineral hot spring pools, day passes, and overnight rooms that include breakfast.

Puyehue, Los Lagos

A forest resort spa in Puyehue, Chile, with volcanic thermal pools and outdoor baths, open only to hotel guests.

Scottsdale, Arizona

Hammam-inspired hotel spa at Omni Scottsdale Resort & Spa at Montelucia in Paradise Valley, with private suites and massage, facial and body treatments for

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.

Calistoga, California

A historic hot-springs resort in Calistoga with an early-1900s mineral pool, mud baths, and a public restaurant, but spa access is limited to hotel guests.

Tyrol, Bavaria

Hotel spa in Kreuth-Reitrain near Tegernsee with a 3,000 sqm onsen-style bathing area, hot and cold pools, saltwater pools and sauna, open on a day-pass basis.

Afyonkarahisar

Resort hotel in Afyonkarahisar built around thermal pools, spa treatments and physical therapy, open to hotel guests.

Palm Springs, California

A hotel-guests-only desert resort in Desert Hot Springs built around natural mineral hot spring pools, with spa treatments and overnight stays.