Spas with thermal pool

Stockholm, Stockholm County

A hotel spa on Södermalm with indoor and outdoor pools, a dry sauna and a steam room, open to day-pass visitors aged 16 and up.

Strongsville, Ohio

Membership-style wellness studio in Strongsville with sauna, steam room and thermal pool, plus a $49 unlimited day pass for first-time visitors.

Portland, Oregon

A member-run bathhouse in Concordia with a clothing-optional salt-water hot pool, cedar sauna and courtyard, day passes from $18.

Gero, Gifu

An outdoor-only onsen in Gero with rock-built baths, a cascade bath and three-temperature pools, open daily except Thursdays.

Miami, Florida

Hotel spa inside Dua Miami, Autograph Collection in Brickell, open daily 9am-6pm, with sauna, steam room, cold plunge and couples massage rooms.

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.

Florence, Tuscany

A 650-square-meter spa inside a 14th-century Florence monastery, with thermal pool, guesthouse rooms, bistro and day-pass access.

Durango, Colorado

A hot springs resort in the Animas Valley near Durango, Colorado, with 32 mineral pools, cold plunges, a lap pool and private cedar soaking tubs.

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.

Mývatn, Northeastern Region

A geothermal lagoon by Lake Mývatn in North Iceland, with hot tub, steam cave, swim-up bar and massages, open daily noon to 10pm.

Eger, Heves

Outdoor thermal bath complex in Eger with sulfurous and radon medicinal pools, family pools and a slide pool, open daily from 9am to 7pm.

Palm Springs, California

Moroccan-themed inn in Desert Hot Springs with natural mineral hot springs, a spring-fed pool and day-pass access from 9am to 4pm.

Noosa, Queensland

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

San Miguel de Allende, Guanajuato

Family-friendly hot springs park near San Miguel de Allende with indoor and outdoor thermal pools, a kids' splash area, and day passes for walk-ins.

Pärnu, Pärnu County

Thermal bath complex in Pärnu with pools, saunas and hot tubs, open daily 7:30–21:30, day passes from €15 on weekdays.

Bad Füssing, Bavaria

Large thermal bath complex in Bad Füssing with 17 indoor and outdoor pools, a sauna area and therapy basins, open daily year-round.

Montego Bay, Saint James

A 12-treatment hotel spa at Half Moon resort in Montego Bay, with a waterfall-fed lagoon pool, steam rooms and outdoor yoga, open to resort guests only.

Houston, Texas

Day spa in Houston's Westside with a grotto pool, outdoor pool, steam rooms and sundeck, plus an on-site restaurant; walk-ins welcome.

Baden-Baden, Baden-Württemberg

A Renaissance-era thermal bathhouse in Baden-Baden built in 1877, offering a structured Roman-Irish bathing ritual for about 39 euros a day.

Calistoga, California

A Calistoga hot springs spa built around mud baths, with private couples rooms and mineral pools open daily from 8am to 11pm.

The Hamptons, New York

Oceanfront resort spa in Montauk with a seawater and marine-based treatment menu, hydrotherapy, contrast bathing, and a heated saltwater pool.

Hajdúszoboszló, Hajdú-Bihar

A medical thermal bath in Hajdúszoboszló, Hungary, with iodine-bromine-salt water pools treating rheumatic and joint conditions, open daily 7am–7pm.

Hakone, Kanagawa

Day-use hot spring in Tōnosawa, Hakone, styled like an old farmhouse village, with communal baths and 19 private open-air rental baths.

Hanmer Springs, Canterbury

New Zealand's largest geothermal hot pool complex in Hanmer Springs, with pools from 28°C to 42°C, a lazy river, slides and alpine views.