Spas with walk-ins welcome

Sapporo, Hokkaido

Natural hot spring inside Sapporo's Jasmac Plaza Hotel in Susukino, open to day visitors and hotel guests alike, with sauna and a rest lounge.

Arima Onsen, Hyogo

A moderately priced onsen bathhouse in Arima Onsen, Kobe, with a forest sauna, a large outdoor bath, yoga and an award-recognized restaurant.

Nashville, Tennessee

A Germantown contrast therapy studio with private suites pairing infrared sauna, cold plunge and a vitamin-c shower; day pass is $70.

Charleston, South Carolina

Contrast therapy studio in Mt Pleasant offering private 60-minute sessions with infrared sauna, cold plunge and vitamin-c shower; day pass $60.

Palm Beach, Florida

A Palm Beach Gardens studio offering 60-minute private-suite sessions combining infrared sauna, cold plunge and vitamin-c shower.

Charleston, South Carolina

Private contrast-therapy suites with infrared sauna, cold plunge and vitamin C shower in West Ashley, Charleston, by reservation.

Sárvár, Vas

Large thermal bath complex in Sárvár with indoor and outdoor pools, a sauna world, slides for kids, and medical spa treatments.

Sárvár, Vas

A large thermal and wellness complex in Sárvár with indoor and outdoor medicinal pools, slides, a sauna world, fitness center and massage treatments.

Koh Samui, Surat Thani

A forest day spa on Koh Samui built around granite steam caves, waterfalls and plunge pools, open daily with walk-in or day-pass access.

Ibusuki, Kagoshima

Oceanfront outdoor onsen in Ibusuki where the two gender-assigned baths swap daily, with views of Mount Kaimon, the East China Sea, and Take-yama.

Merano, Trentino-South Tyrol

Central thermal bath complex in Merano with 25 pools, a sauna world, thermal park and medical spa area, open daily year-round with walk-in day passes.

Charleston, South Carolina

Hotel spa in Ansonborough with cypress-clad treatment rooms, a signature citrus facial, and a second-floor fitness studio; walk-ins welcome.

Atlanta, Georgia

A medical spa in Atlanta's Five Points district offering walk-in treatments, a private lounge, refreshments and luggage storage.

Wanaka, Otago

A lakefront wood-fired sauna at The Outlet in Wānaka running guided or self-guided group sessions with cold dips in the lake between rounds.

BAITING HOLLO, New York

A 10,000-square-foot spa and hair salon in Baiting Hollow with couple's suites, saunas and steam rooms, part of the East Wind resort on Long Island.

Santa Ynez, California

Adults-only resort spa inside Chumash Casino Resort in Santa Ynez with 21 treatments, a mineral pool, cold plunge and couple's suites.

Hunter Valley, New South Wales

Large day spa at Chateau Elan in Hunter Valley with 17 treatment rooms, a float tank, outdoor mineral spas and couples' treatments; day passes and walk-ins

Las Vegas, Nevada

An adults-only hotel spa inside Encore Las Vegas with whirlpool, sauna and steam room, open daily for treatments and day passes, walk-ins welcome.

Vail, Colorado

A day spa and recovery club in downtown Vail with hot tub, sauna, steam room, cold plunge and salt lounge, plus day passes and fitness access.

Tucson, Arizona

Six-room hotel spa at Hacienda del Sol in Tucson, open daily 9-6, taking both resort guests and local walk-ins for massages, facials and body treatments.

New York City, New York

A penthouse-level spa at Hotel Chelsea in Manhattan with a rooftop terrace, sauna, steam rooms and a 16-treatment menu for guests 18 and over.

Sonoma, California

A luxury day spa in Sonoma with a Relaxation Garden, steam room and hot tub, open daily 9am–7pm with walk-in day passes.

Boston, Massachusetts

A luxury hotel spa in Boston's Back Bay with a Crystal Steam Room, Vitality Pool and private couples suites, open to adults 18 and over.

Taipei

Hotel spa in Taipei's Songshan district with private suites, sauna, steam room and a heated outdoor pool, open daily with day passes for non-guests.