Spas with thermal pool

Lake Tahoe, California

Family-friendly hot springs resort near Lake Tahoe with outdoor pools, private indoor soaking rooms and saunas, open daily on a walk-in basis.

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.

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.

Hot Springs, Arkansas

Thermal-water bathhouse on Central Ave in Hot Springs offering soaking pools, private mineral baths and eight spa treatments, minimum age 14.

Scuol, Grisons

Hotel spa at the 4-star Belvedere in Scuol with indoor/outdoor pools, mineral and thermal water, sauna, steam bath and a day pass option.

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.

Palm Springs, California

A 38,000-square-foot resort spa at JW Marriott Desert Springs in Palm Desert offers day passes, saunas, a saltwater lap pool and couples suites.

Idaho City, Idaho

A reservation-only hot springs soak in Idaho City with private tubs, a steam room and a $30 day pass, open five days a week.

Philadelphia, Pennsylvania

Hotel spa in Center City Philadelphia with a heated indoor saltwater pool, fitness center and day-pass access for non-guests.

The Colony, Texas

A day-soaking spa in The Colony with mineral pools at varying temperatures, seven saunas, cold plunges and a poolside café.

Hunter Valley, New South Wales

A resort spa inside Avani Cypress Lakes in Pokolbin, open to hotel guests for treatments, thermal pools, outdoor baths and a fitness and yoga space.

Cancún, Quintana Roo

A boutique hotel near Cancún airport with a small wellness wing — pool, jacuzzi, sauna, steam room and temazcal — open to day-pass visitors.