Spas with reservation required

Philadelphia, Pennsylvania

A head spa in Queen Village, Philadelphia, focused on scalp and hair treatments, with private suites and a $300 signature service.

Napa Valley, California

Hotel day spa atop the Archer in downtown Napa with a water deck, fitness studio access and treatment rooms; reservations required.

Saratoga Springs, New York

Historic 1935 bathhouse in Saratoga Springs offering mineral water soaks and massages in original tubs, reservation only, moderate pricing.

Karlovy Vary, Karlovy Vary Region

A one-room beer bath spa in a 18th-century cellar in central Karlovy Vary, with unlimited beer, oak tubs and a straw-bed rest area.

Františkovy Lázně, Karlovy Vary Region

A private beer-bath spa in Františkovy Lázně where you soak in oak tubs with hop and yeast extracts and drink unlimited Krušovice beer.

Seattle, Washington

An adults-only wellness studio near Green Lake with private infrared sauna suites, therapeutic massage and red light therapy by reservation.

Scottsdale, Arizona

A Thai-inspired day spa in North Scottsdale offering massage, facials and a signature Waterfall Scalp Spa treatment in private rooms.

Asheville, North Carolina

A Japanese-inspired destination spa on a mountainside outside downtown Asheville, built around private outdoor salt hydrotherapy tubs and massage.

Sopot, Pomerania

A medical resort spa in Sopot built around local brine and mud treatments, open to hotel guests by reservation rather than day visitors.

Santa Barbara, California

A downtown Santa Barbara day spa built around a private infrared sauna, salt room, cold plunge and a sound-and-light meditation pod, booked by appointment.

Austin, Texas

Adults-only hotel spa at the Fairmont Austin with nine treatment rooms, a hydrotherapy circuit, sauna and cold plunge, open daily with day passes available.

Dallas, Texas

Hotel spa inside The Adolphus in downtown Dallas, with six treatment rooms, a couple's suite and a 22-item menu of massages, facials and body treatments.

Carmel-by-the-Sea, California

Resort spa at Carmel Valley Ranch with 12 treatment rooms, private terraces, a saltwater pool and infinity hot tub, open to adults by reservation.

San Diego, California

Adults-only day spa at Mission Bay Resort with massage, facials, Himalayan salt treatments and couples suites; walk-ins and day passes welcome.

Palm Springs, California

Hotel spa at the Renaissance Esmeralda in Indian Wells offering desert-inspired treatments, a recovery lounge, steam rooms and day passes, adults only.

Piešťany, Trnava Region

Spa Irma on Piešťany's spa island offers historic mud and mirror thermal pools, a hydrotherapy circuit and a 60-treatment medical spa menu, adults only.

Palm Springs, California

Adults-only hotel spa at Tommy Bahama Miramonte in Indian Wells with 15 treatments, eucalyptus steam rooms, a hydrotherapy jacuzzi and saltwater pool.

Austin, Texas

Hotel spa at Hotel Viata in West Lake Hills with treatment rooms, a couples suite, pool, sauna, steam room and a day-pass option for amenity access.

Essaouira, Marrakesh-Safi

A budget hammam and day spa in Essaouira's medina offering scrub treatments, massages, hair and nail services, open daily 10am-8pm.

Orlando, Florida

Upscale day spa at Bella Collina private club near Orlando, open Tuesday–Sunday by appointment, with massages, facials and couples suites.

San Diego, California

Hotel spa at the historic Hotel del Coronado with an ocean-view pool, 20 treatments, and a seaweed-based signature Ocean Essence Ritual.

Austin, Texas

A fifth-floor hotel spa inside JW Marriott Austin with eight treatments, a heated rooftop pool and a 16-plus minimum age.

Naples, Florida

Upscale day spa in Naples offering infrared sauna, massage, facials and foot detox, with a $230 signature massage and couples packages.

Los Cabos, Baja California Sur

A hotel spa at Corazón Cabo Resort offering massages, facials and a hydrotherapy circuit with sauna, steam room and hot tub, no day passes sold.