Spas with hot tub

Calistoga, California

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

Vail, Colorado

Hotel spa and recovery club in Vail Village with hot tubs, cold plunge, sauna, salt room and a gym, open to day-pass visitors.

Doha

Hotel spa at The Westin Doha with some of the city's largest wet facilities, accessible to hotel guests and members only, no day passes sold.

Nashville, Tennessee

A Finnish-inspired bathhouse and salon in a converted East Nashville factory, with sauna, steam room, cold plunge and private suites for couples.

Opatija, Primorje-Gorski Kotar

A 5-star hotel spa in Opatija with a sauna centre, seawater pools and couples treatments, open only to Hotel Ambasador guests.

Krynica-Zdrój, Lesser Poland

Mountain resort spa in Krynica-Zdrój with indoor and outdoor pools, a sauna complex, and a clothing-optional 18+ zone; day passes available.

Velingrad, Pazardzhik

Hotel spa in Velingrad with mineral-water pools, saunas, steam rooms and a hammam spread over 4,000 square metres; day passes are available.

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

Beppu, Oita

A hot-spring bathhouse in Beppu's Kannawa district, running since 1922 on 100% unblended spring water with walk-in day passes.

Miami, Florida

A co-ed Turkish hammam and day spa in North Miami offering a $125 day pass with saunas, steam rooms, a hydromassage pool and an on-site Turkish restaurant.

New York City, New York

A 24-hour Korean jjimjilbang-style day spa in Midtown Manhattan with saunas, a soaking tub, and a $135 body-scrub signature treatment.

Bursa

A historic thermal bathhouse and small hotel in Bursa's Kükürtlü district, with separate men's and women's hamams, day passes, and overnight stays.

San Diego, California

A walk-in day spa in San Diego's Hillcrest neighborhood with massage, cryotherapy, salt therapy and a $100 all-day wellness pass.

Bishop, California

A century-old natural hot springs pool near Bishop in the Eastern Sierra, with a cooling waterfall, a separate hot soak, and simple day-use facilities.

Chicago, Illinois

Day spa in Burr Ridge, about 20 miles outside Chicago, built around a hydrotherapy circuit with whirlpool, cold plunge and steam room.

Austin, Texas

Lakeside day spa near Austin offering a $150 day pass with pools, steam room, sauna and relaxation lounges, open daily 9am–9pm.

Ein Bokek, Southern District

Hotel spa on the Dead Sea shore in Ein Bokek with a heated mineral-water pool, sulphur pools, hammam and sauna; day passes open to adults 16 and up.

Santa Cruz, California

A communal hot-tub and sauna garden in Santa Cruz, modeled on a Japanese bathhouse, with day passes, private rooms, and massage add-ons.

Lake Tahoe, California

Boutique day spa in Truckee with a co-ed thermal suite, massage, facials and non-toxic nails, plus a $50 drop-in hot tub, sauna and cold plunge pass.

Los Angeles, California

A budget-friendly day spa inside the Commerce Casino complex near Los Angeles, with saunas, steam rooms, jacuzzis and massages from $68.

Napa Valley, California

A family-run day spa in Vacaville near Napa Valley, offering massage, facials, waxing and a private whirlpool tub by appointment only since 1997.

San Francisco, California

Neighborhood day spa in Noe Valley with a private outdoor hot tub, offering massage and a combined soak-and-massage package for two.

Vail, Colorado

Hotel spa at The Arrabelle in Lionshead Village, Vail, with 11 treatment rooms, a fitness center and locker-room steam rooms, open to hotel guests.

Bad Reichenhall, Bavaria

A sole-water thermal bath in Bad Reichenhall with indoor-outdoor pools, an underground salt grotto, sauna area, fitness center and family pool, open daily