Spas with moderate

Krynica-Zdrój, Lesser Poland

Mountain resort spa in Krynica-Zdrój with indoor and outdoor pools, a sauna complex, and a clothing-optional 18+ zone; day passes available.

Portland, Oregon

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

Portland, Oregon

A Finnish-style sauna and bodywork space in Portland's Hosford-Abernethy area, open daily with walk-in and membership access.

Berlin

A hotel spa inside The Mandala Hotel in Mitte, Berlin, with sauna and fitness areas, day passes for adults 14 and up.

Los Angeles, California

Women-only Korean day spa in Koreatown, LA with saltwater, mineral and cold pools, a salt room, and walk-in day passes.

Hudson, New York

Adults-only communal thermal baths and steam room in downtown Hudson, NY, with day passes, memberships and treatment-plus-soak packages.

Washington, D.C., District of Columbia

A Georgetown studio in Washington, D.C. offering private infrared sauna cabins and float therapy suites, bookable by reservation only.

Birmingham, Michigan

A Birmingham, Michigan day spa built around waterless volcanic rock treatments, with V-steam, facials, massage and a steam room for adults and couples.

Dallas, Texas

A membership-based recovery studio in Dallas's Cityplace offering cryotherapy, infrared sauna, compression, IV drips and skin treatments by reservation only.

Tucson, Arizona

Adults-only hotel spa at El Conquistador Tucson with a salt therapy lounge, heated outdoor pool and mountain views, day passes available to hotel guests.

Denver, Colorado

A 6,000-square-foot hotel spa in downtown Denver's Granite Tower, open to day-pass visitors 18 and older for $40 to $75.

Galway, Connacht

Adults-only hotel spa in Galway with a thermal suite, hydro pool and sauna; day pass runs about €50 and reservations are required.

Palm Springs, California

A 16-room adults-only hotel in Desert Hot Springs with three natural mineral-water pools fed by a 350-foot geothermal well, plus a small on-site spa and

Rogaška Slatina, Savinjska

Wellness center at Grand Hotel Rogaška in Rogaška Slatina, Slovenia, with pools, saunas and fitness; day pass available by reservation.

Seattle, Washington

A women-only membership spa in West Queen Anne offering massage, lymphatic drainage and red light therapy, with no day passes or walk-ins.

Sun Valley, Idaho

A 50,000-square-foot health club and spa in Ketchum with saltwater pools, a full gym and massage, facial and other spa treatments.

Atlanta, Georgia

A hotel spa and wellness club inside Loews Atlanta Hotel in Midtown, built around hammam, sauna, steam room and a monthly membership rather than drop-in visits.

Park City, Utah

A Park City studio pairing private infrared sauna cabins with float therapy tanks, booked by reservation, with membership options for regulars.

Sedona, Arizona

Day spa in Sedona with eucalyptus steam rooms, saunas, jacuzzi and a fitness center, offering day passes and memberships for walk-in guests.

Brežice, Posavje

A large thermal water park in Brežice, Slovenia, with a year-round indoor pool riviera, an adults-only sauna zone, and seasonal outdoor slides.

San Diego, California

A day spa in University City, San Diego, open since the late 1990s, offering facials, massage and lymphatic drainage with a monthly membership option.

Houston, Texas

Westside Houston day and med spa with treatment menu plus an H-Circle membership for $99/month, open daily with day passes available.

New York City, New York

Adults-only day spa in Maplewood, NJ, offering deep tissue massage, bodywork and facials by appointment, open daily 9am-8pm.

Santa Fe, New Mexico

A walk-in recovery studio in Santa Fe's DeVargas Center offering cryotherapy, infrared sauna, compression, red light and IV drip therapies.