Spas with outdoor baths

Chicago, Illinois

Thermal baths and spa rituals in a restored 1902 factory in West Town, Chicago, open daily for adults-only soaking and massage packages.

Ainsworth, British Columbia

A lakeside hot springs resort in British Columbia's Kootenays with public thermal pools, a spa, restaurant and overnight rooms, closed Tuesdays.

Palm Springs, California

Adults-only hot springs resort on Miracle Hill in Desert Hot Springs with private mineral tubs, a Finnish sauna, salt room and 35 spa treatments.

Banff, Alberta

A historic outdoor mineral pool run by Parks Canada on Sulphur Mountain in Banff, open daily and walk-in only, no reservations.

Calistoga, California

A moderate-priced resort spa in Calistoga with geothermal mineral pools, open daily 9am-5pm and offering day passes to the public.

Houston, Texas

A Houston day spa near Memorial Park focused on massage and bodywork, with a spa pool, sauna and outdoor retreat, open daily 10am-8pm.

Miami, Florida

A beachfront resort spa in North Beach, Miami with cryotherapy, a floating salt bath, sauna, steam and a cold plunge, open to walk-ins and day-pass guests.

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.

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.

Tabernash, Colorado

A resort spa at Devil's Thumb Ranch in Tabernash, Colorado, open only to overnight guests, with a geothermal pool, hot tub and couples treatments.

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.

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.

Jackson Hole, Wyoming

A day spa next to the Trailborn hotel in Jackson Hole with an outdoor pool deck, salt lounge and day passes for walk-in soaks or treatments.

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.

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.

Tuscany

Hotel spa inside Florence's Four Seasons, with a walled garden pool, whirlpool, sauna, steam room and couples suite, open to day-pass guests.

Gero, Gifu

Gero's riverside hot-spring source pool in the town center, where visitors can touch the water and take photos, though full bathing has been banned since

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.

Calistoga, California

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

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

Saratoga Springs, New York

A floating Nordic-style sauna moored on Saratoga Lake, with a 15-person cabin, roof terrace and lake plunge, open daily except Monday.

Tucson, Arizona

Hotel spa at Omni Tucson National Resort with 12 treatment rooms, a couples suite, salon services, and day passes open to both guests and locals.

Monroe, Utah

Natural hot spring pools fed by mineral water in rural Monroe, Utah, open 24/7 with day-pass soaking and funky bus and cabin lodging on site.