Spas with thermal pool

Wiesbaden, Hesse

Historic thermal-water day spa inside Wiesbaden's Hotel Schwarzer Bock, with sauna, steam room, pool and day passes for solo visitors, couples and groups.

Temescal Valley, California

Adults-only hot springs resort in Temescal Valley with 19 outdoor mineral pools, red clay baths, and a cave-like grotto, open daily 9:30am-5pm.

Houston, Texas

Upscale day spa at The Houstonian in Houston with 22 treatment rooms, soaking pools and a sundeck; pool access comes with a 50-minute-plus treatment, not a

Scottsdale, Arizona

North Scottsdale day spa with massage, facials, sauna, steam and a thermal pool, plus private suites for couples and groups.

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

Montreal, Quebec

Indoor Nordic spa in Old Montreal offering a hot-and-cold thermal circuit, massages and a relaxation lounge, open daily with day passes and valet parking.

Seattle, Washington

A reservation-only social wellness sauna spa in Renton (serving the Seattle area) with a thermal pool, cold plunge, sauna and steam room, day passes from $75.

Calistoga, California

A 20-treatment hotel day spa in Santa Rosa with an indoor caldarium plunge pool, eucalyptus steam rooms, and walk-in or reserved day passes for adults 18+.

Rocky River, Ohio

Massage-focused day spa in Rocky River offering couples treatments, sauna, steam room and thermal pool, open daily by appointment.