Spas with walk-ins welcome

Barcelona, Catalonia

Adults-only thermal baths in a converted 18th-century building near Barcelona's Born market, with soaking pools, massages and couples rituals.

Amman

A hotel hammam in Tla al-Ali, Amman, with marble bathing halls, a hot pool, sauna and Jacuzzi, offering about 20 treatments from a basic scrub to a $120

Bad Gastein, Salzburg

Thermal baths in Bad Hofgastein with indoor/outdoor pools, bathing lakes, slides, saunas and a sports medicine center, open daily year-round.

Aspen, Colorado

A reservation-only Aspen studio offering private sound, energy and subconscious-journey sessions instead of classic spa treatments.

Aspen, Colorado

A medical spa in Aspen's Airport Business Center offering non-surgical facials and laser treatments, with walk-ins welcome on weekdays only.

Las Vegas, Nevada

Adults-only hotel spa at Resorts World Las Vegas with a six-pool hydrotherapy circuit, salt room, and a themed Aufguss sauna show on weekends.

Geneva

A central Geneva adults-only club built around a sauna, hammam and jacuzzi, with nightly themed events for swingers, couples and gay visitors since 1999.

Washington, D.C., District of Columbia

A multi-level day spa near DC with indoor and rooftop hydrotherapy pools, several sauna types, lounges, an a la carte spa menu and eateries.

Seattle, Washington

A Russian-style bathhouse in South Lake Union with a hydrotherapy circuit and sauna, open to walk-ins daily except Monday, adults only.

Austin, Texas

Medical spa and day spa on South Lamar offering facials, injectables, massage and a signature $1,499 Mermaid Lift, open daily with private rooms and a stocked

New York City, New York

A Flatiron bathhouse with six thermal pools, a banya, dry and infrared saunas, a steam room and a salt pool, day pass from $39.

Miami, Florida

Day spa in the Sherry Frontenac Hotel's lower lobby in Miami Beach, with sauna, steam, cold plunge and thermal pool alongside massage treatments.

Chicago, Illinois

Hyde Park day spa since 1978 offering facials, massage, body treatments, waxing and hydrotherapy, with walk-ins welcome.

Los Angeles, California

A clothing-optional Korean-style bathhouse in East Hollywood built over LA's only natural mineral hot spring, with soak pools, steam room and sauna.

Kuala Lumpur

An onsen-style day spa in Kampung Baru, Kuala Lumpur, with thermal pools, sauna, steam room and couples treatments.

Portland, Oregon

Neighborhood day spa in Portland's Overlook area with a private soak-and-steam retreat studio, massage, skincare and nail services.

Napa Valley, California

A boutique day spa in downtown Napa Valley with nine treatment rooms offering massage, facials and body work, plus sauna, steam and a thermal pool.

Scuol, Grisons

A year-round thermal bathing complex in Scuol with indoor-outdoor mineral pools, a brine pool, cold and warm grottos, and a fireside lounge.

Bormio, Lombardy

Family-friendly thermal baths in Bormio with chlorine-free pools heated to 37–40°C, plus sauna, steam room and adult-only wellness areas.

Hot Springs, Arkansas

Historic 1912 bathhouse on Bathhouse Row offering walk-in thermal mineral baths, steam cabinet and Swedish massage, no appointment needed.

Sacramento, California

Day spa in Sacramento's Oak Park with float rooms, private cold plunge and sauna suites, infrared sauna, and a Somadome meditation pod.

Baden-Baden, Baden-Württemberg

Modern thermal baths in Baden-Baden with indoor-outdoor pools and a Roman-style sauna garden, open daily 8am–10pm, day pass €40.

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.