Spas with reservation required

Seattle, Washington

A private floating bathhouse on Seattle's Lake Union, booked out entirely for one group of up to 12 for sauna, cold plunge and hot tub rounds.

Miami, Florida

Hotel spa inside Dua Miami, Autograph Collection in Brickell, open daily 9am-6pm, with sauna, steam room, cold plunge and couples massage rooms.

Palm Springs, California

Hotel spa inside the Avalon in Palm Springs, open Thursday through Monday, with a $75 day pass covering jacuzzi, sauna, cold plunge and steam rooms.

Oslo

Waterfront sauna spot on Aker Brygge with shared and private saunas, sea bathing, and sauna boat trips on the fjord.

Cotswolds, England

A woodland sauna and ice bath venue near Northleach in the Cotswolds, offering communal and private heat-and-cold sessions plus occasional workshops.

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.

London, England

A Russian-style banya bathhouse in Belgravia offering oak-lined steam rooms, cold plunge pools and leaf-massage rituals, with day passes by reservation only.

Calistoga, California

A 20-treatment hotel day spa in Santa Rosa with an indoor caldarium plunge pool, eucalyptus steam rooms, and walk-in or reserved day passes for adults 18+.

Philadelphia, Pennsylvania

Hotel spa in Center City Philadelphia with a heated indoor saltwater pool, fitness center and day-pass access for non-guests.

Scottsdale, Arizona

Hotel spa inside Hotel Solaya in South Scottsdale built around Tod Miller's proprietary BodyWalking compression technique, with four treatments and a $335

Austin, Texas

Hotel spa inside Austin Proper with 15 treatments, a cold plunge and sauna recovery room, open daily by reservation.

Dallas, Texas

Hotel ZaZa's spa in Oak Lawn offers massage and skincare treatments with valet parking and pool access, but no standalone day pass.

Tallinn, Harju County

A small hotel spa in central Tallinn with three treatment rooms, two saunas and a Japanese pool, offering massages and facials by appointment.

Orlando, Florida

Hotel spa at the Rosen Centre on International Drive in Orlando, offering massages, facials, nail care and access to a steam room, pool and fitness center.

Cotswolds, England

A wood-fired riverside sauna at Whichford Mill in the Cotswolds, with a cold-plunge bath, river dipping, and both private and communal sessions.

Sedona, Arizona

A hotel spa inside a Mission/Arts & Crafts style bed and breakfast inn in Sedona's Red Rock Country, open daily 9am–5pm by reservation.

Hudson Valley, New York

A French-inspired hotel spa in the center of Rhinebeck village, open to overnight guests by reservation.

Carmel-by-the-Sea, California

A hotel spa inside Carmel-by-the-Sea's Hyatt Regency Monterey property, with hydrotherapy, sauna and a relaxation lounge for guests and couples.

Naples, Florida

A hotel spa inside the Inn on Fifth in downtown Naples, open daily for massages, facials, nail services, sauna, steam room and lounge access.

Houston, Texas

A hotel spa inside The Laura Hotel in downtown Houston offering massage, facial and nail treatments for solo visitors, couples and groups.

Arima Onsen, Hyogo

Hotel spa in Arima Onsen with Arima's rare iron-rich "ginsen" waters, outdoor baths, sauna and jacuzzi, run as an all-inclusive overnight stay.

Prague

A beer-spa and wellness venue in Prague's Nové Město district offering beer-bath tubs, massages, and a saunarium, open daily from 11am to 11pm.

Kyle, Texas

A 88-acre Hill Country resort near Kyle and Wimberley with overnight rooms, a garden spa, pool, hot tubs and day-pass access by reservation.

Tulum, Quintana Roo

A hotel spa in Tulum's SM 15 area that requires advance reservations and is geared toward couples and small groups, priced in the upscale range.