Spas with adults only

San Francisco, California

Adults-only Russian bathhouse in San Francisco's India Basin with steam rooms, cold plunge, rooftop deck and a café, open daily except Tuesday.

Washington, D.C., District of Columbia

Hotel spa inside the Watergate Hotel with a retro indoor pool, whirlpool, dry sauna and steam room, plus a day pass for treatments and amenities.

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.

Nashville, Tennessee

Upscale hotel spa inside 1 Hotel Nashville with 38 treatments, an infrared sauna wrap, and an 18-plus minimum age; no day pass offered.

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.

San Diego, California

Thai massage studio in San Diego's Gaslamp Quarter offering massage, head spa, body scrub and infrared sauna, walk-ins welcome daily.

Portland, Oregon

A member-run bathhouse in Concordia with a clothing-optional salt-water hot pool, cedar sauna and courtyard, day passes from $18.

Washington, D.C., District of Columbia

24/7 men's bathhouse in Logan Circle with sauna, steam room, lounge, and private rooms, clothing optional, 18+ with ID.

Austin, Texas

Contrast therapy studio in East Austin with a communal garden sauna-and-cold-plunge setup, private suites, and red light sessions, day passes from $25.

Vail, Colorado

Adults-only day spa at The Charter at Beaver Creek with saltwater pools, steam room, sauna and a day pass for treatments or facility access.

New York City, New York

Hotel spa inside Thompson Central Park combining massages, facials and body treatments with daily fitness classes and private saunas, near Central Park.

Scottsdale, Arizona

Day spa in South Scottsdale focused on facials and a signature holistic massage, with sauna, steam room, thermal pool and cold plunge on site.

Columbia, Maryland

A luxury medical and day spa in Columbia's Town Center combining facials, massage and laser/injectable treatments with a thermal pool, sauna and steam room.

Philadelphia, Pennsylvania

A reservation-only traditional Nordic sauna in North Philadelphia, open Wednesday through Monday and closed Tuesdays.

Philadelphia, Pennsylvania

Day spa in Northeast Philadelphia with a full hydrotherapy circuit of saunas, hammam, cold plunge and pools for a $60 day pass.

New York City, New York

A below-street-level day spa in NoHo with thermal baths, a three-story indoor waterfall, sauna, steam room and cold plunge, plus massage and facial treatments.

Santa Fe, New Mexico

Santa Fe float spa with sensory-deprivation tanks and infrared sauna rooms, walk-ins accepted when the schedule allows.

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.

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.

Boston, Massachusetts

A Finnish kelo-log banya in Newton with sauna, steam room and cold plunge, alternating men's and women's days, day passes from $69.

Chantilly, Virginia

King SPA is a Korean bathhouse in Chantilly, VA, with gender-separated clothing-optional baths, mixed saunas, a restaurant, and day passes for walk-ins.

Chicago, Illinois

A 24-hour Korean bathhouse and sauna complex in Niles near Chicago, with 11 heat rooms, hot and cold pools, and a $45 day pass covering walk-in access.

Lake Como, Lombardy

A day spa inside the Castello di Casiglio parkland near Erba, offering a 3-hour pass with heated indoor-outdoor pools, saunas and a Turkish bath; adults and

Portland, Oregon

A Finnish-style sauna bathhouse in Portland's Boise neighborhood offering day passes, memberships, and a handful of massage and facial treatments.