Spas with thermal pool

Napa Valley, California

Adults-only resort spa in Napa Valley with pools, sauna, steam and a fitness center, open to hotel guests and club members via day pass.

Edinburgh, Scotland

Hotel spa inside The Caledonian on Princes Street with a thermal pool, sauna, steam room and relaxation lounge, open daily 6am to 9pm.

Phoenix, Arizona

Adults-only hotel wellness setup in downtown Phoenix with a heated pool, sauna and steam room, day passes available for $50.

Ischia, Campania

A day-pass thermal park in Serrara Fontana on Ischia with multiple pools, a restaurant, and family-friendly access, open daily 9am to 6pm.

Bad Ragaz, St. Gallen

A resort thermal spa in Bad Ragaz with indoor and outdoor thermal pools and sauna, open daily 7:30am–8pm, reservation required for day passes.

Tucson, Arizona

A hotel spa at an 80-acre Sonoran Desert resort in Tucson, open to overnight guests, with three pools, hot tubs, sauna and yoga classes.

Sedona, Arizona

Hotel spa at Hilton Sedona Resort at Bell Rock offering day passes with a relaxation lounge, steam room, sauna and thermal pool, open daily 6am-8pm.

Buxton, England

A hotel spa built into Buxton's historic Crescent, centred on a thermal pool, hydrotherapy circuit and salt room, open to hotel guests only.

Ubud, Bali

A 22-acre riverine-forest wellness retreat outside Ubud built around a sacred spring, accessible only to guests staying at the estate.

Sedona, Arizona

Hotel spa near Bell Rock in Sedona with sauna, steam room, cold plunge and pools, open to resort guests only.

Boston, Massachusetts

A hotel spa inside Mandarin Oriental, Boston's Back Bay property, open to hotel guests only, with sauna, steam room, pools and a cold plunge.

Ramona, California

A vacation-rental resort in Ramona whose day-spa access, sauna, steam room and heated pool are reserved for guests staying on the property.

Saturnia, Tuscany

A hotel spa near Terme di Saturnia with an infinity pool, hot tub, rooftop terrace and restaurant, offering day passes for non-guests.

Los Angeles, California

A hotel spa at Shade Hotel Redondo Beach with sauna, steam, pools, cold plunge and thermal circuits, open to hotel guests overlooking the marina.

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.

Chianciano Terme, Tuscany

Hotel spa in Chianciano Terme open to non-guests, built around a 450 sqm holistic water, color and massage circuit.

San Diego, California

Hotel spa at Carté Hotel San Diego Downtown with a heated saltwater pool, whirlpool, 28,000 sq ft fitness club with sauna and steam room, open to guests only.

Oaxaca

An all-inclusive beachfront resort spa in Huatulco with a sauna, steam room and thermal pools, open only to hotel guests.

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.

Calistoga, California

A 25-room Sonoma hotel in Forestville with a spa barn offering sauna, steam and pools, mainly for overnight guests.

Afyonkarahisar

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

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.

Sedona, Arizona

A 23-casita destination spa resort inside Sedona's Boynton Canyon, open to overnight hotel guests 16 and older for multi-day wellness journeys.