Spas with hydrotherapy circuit

Portorož, Coastal-Karst

Thermal baths and seawater pools in Portorož, open daily 7am–9pm with walk-in day passes and a large sauna park.

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

Hot Springs, Arkansas

Historic 1924 thermal bathhouse inside the Arlington Hotel in Hot Springs, offering mineral baths, sauna and massage, with walk-ins welcome.

Boston, Massachusetts

A Norwood, Massachusetts day spa built around a hot-cold hydrotherapy circuit of mineral baths, saunas, steam and cold plunges, open daily with a day pass.

Naples, Florida

A hotel spa at Naples Beach Club with a 3,200-square-foot thermal circuit, rooftop lap pool and body/facial treatments built around ocean and plant themes.

San Diego, California

Adults-only hotel spa in Carmel Valley with a hydrotherapy circuit, two fireplace lounges, and a $100 day pass covering pools and fitness facilities.

New York City, New York

A penthouse-level spa at Hotel Chelsea in Manhattan with a rooftop terrace, sauna, steam rooms and a 16-treatment menu for guests 18 and over.

Park City, Utah

A hotel spa in Park City with seven treatment rooms, hydrotherapy tub and steam rooms, open to guests by reservation, minimum age 16.

Killarney, Munster

A hotel spa in Killarney National Park with an adults-only Vitality Suite of hydrotherapy pool, sauna, steam room and outdoor hot tub.

Asheville, North Carolina

Adults-only hotel spa in Asheville with a fiber-optic-starred lap pool, waterfall pools, saunas and an electronics-free policy; day passes are limited and

Galway, Connacht

Adults-only hotel spa in Galway with a thermal suite, hydro pool and sauna; day pass runs about €50 and reservations are required.

Miami, Florida

Adults-only hotel spa on Belle Isle near South Beach with a hammam, sauna, ice room, infinity pool and a day pass option for non-guests.

Taos, New Mexico

A reservation-only wellness studio in Taos offering hyperbaric oxygen, colon hydrotherapy and infrared sauna sessions aimed at altitude recovery.

Miami, Florida

Hotel spa at The Setai in Miami Beach with 7 ocean-view treatment rooms, 5 couples suites, saunas, steam and a cold plunge.

Gold Coast, Queensland

A 90-minute hydrotherapy circuit in Southport with a Finnish rock sauna, 5° ice baths and hot/cold magnesium pools, day pass $49.

Nashville, Tennessee

Upscale day spa in Franklin outside Nashville offering facials, massages, a salt room, infrared sauna and hydrotherapy tub, open daily by reservation.

New York City, New York

A Brooklyn bathhouse built around the largest banya in the US, with Turkish and Moroccan hammams, multiple saunas and a hydrotherapy pool circuit.

Philadelphia, Pennsylvania

Korean-style bathhouse in Cheltenham, just outside Philadelphia, with themed heat rooms, scrub and massage services, and a fitness center.

Chicago, Illinois

Upscale day spa in Lincoln Park, Chicago, where booking any treatment unlocks all-day access to a hydrotherapy circuit, thermal suite and outdoor terrace.

Mariánské Lázně, Karlovy Vary Region

Medical spa resort in Mariánské Lázně combining balneology, physiotherapy and Ayurveda programs, open only to overnight hotel guests aged 18+.

Hévíz, Zala

A natural thermal lake and medical spa in Hévíz, Hungary, offering mud and weight baths, massage and physiotherapy, open daily 9:00–18:30.

Park City, Utah

A ten-treatment-room spa inside the private Promontory Club in Park City, with a full hydrotherapy circuit of steam, sauna and cold plunge.

Milan, Lombardy

Adults-only day spa in a Liberty-style building near Milan's Parco Sempione, with thermal pools, saunas, steam room and a hydrotherapy circuit.

Portland, Oregon

Day spa and natural medicine clinic in NW Portland's Slabtown with sauna, hydrotherapy, massage, acupuncture and a vegan café on site.