Spas with thermal pool

Saint-Malo, Brittany

A three-in-one day spa in Saint-Malo combining a salt-water aquatic circuit, spa treatments and a fitness club, open daily on a day-pass basis.

Washington, D.C., District of Columbia

A multi-level day spa near DC with indoor and rooftop hydrotherapy pools, several sauna types, lounges, an a la carte spa menu and eateries.

Plainfield, Indiana

Day spa in Plainfield, IN offering facials, massages and body-sculpting treatments alongside a sauna, steam room and thermal pool, reservation required.

Jūrmala

A pool-and-sauna complex inside Pegasa Pils Hotel in Jūrmala, with a 12.5m pool, three saunas, steam room and a salt room; day passes available, minimum age 16.

Noosa, Queensland

Day spa on Hastings Street in Noosa Heads with a hydrothermal circuit, day passes, and walk-ins welcome.

New York City, New York

A below-street-level day spa in NoHo with thermal baths, a three-story indoor waterfall, sauna, steam room and cold plunge, plus massage and facial treatments.

Tenerife, Canary Islands

Hammam and massage spa inside Hotel AluaSoul in Costa Adeje, with a hydrotherapy circuit, Moroccan rituals and day passes for walk-ins.

Saturnia, Tuscany

Walk-in thermal park in the Maremma countryside with four outdoor sulfur pools, hydromassage jets and a vascular circuit fed by a 3,000-year-old spring.

New York City, New York

Korean-style day spa in Edgewater, NJ, with saunas, thermal pools and an infinity pool, open daily 9am–9:30pm, day passes for walk-ins.

Aix-les-Bains, Auvergne-Rhône-Alpes

An upscale day spa inside Hotel Le Riviera in Aix-les-Bains, with pools, saunas, a hammam and eight treatment rooms open to walk-ins.

Taos, New Mexico

Hotel day spa at El Monte Sagrado in Taos with a hydrotherapy circuit, saltwater pool and treatment rooms, open daily, day passes available.

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.

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.