Spas with reservation required

Längenfeld, Tyrol

A large thermal bath and 4-star hotel spa in the Ötztal valley near Längenfeld, with indoor-outdoor pools, a sauna garden and a dedicated kids' water world.

Singapore

Garden-set day spa inside Bishan Park 2 with 12 treatment rooms, outdoor baths, massages and facials using Elemis and Skinceuticals products.

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.

Daylesford, Victoria

A rammed-earth house on 80 hectares near Daylesford, rented whole for up to 10 adults, with in-room massage and a two-night minimum stay.

Asheville, North Carolina

A downtown Asheville salt cave with Himalayan salt walls, a hammam steam bath and massage rooms for solo visitors and couples, reservation-based.

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.

Palm Springs, California

Adults-only hot springs resort on Miracle Hill in Desert Hot Springs with private mineral tubs, a Finnish sauna, salt room and 35 spa treatments.

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.

Aspen, Colorado

A downtown Aspen wellness studio offering sauna, cold plunge, IV drips, hyperbaric oxygen, red light therapy and sports massage, open daily 10am–6pm for adults.

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.

Miami, Florida

A luxury day-pass wellness circuit inside Carillon Miami Wellness Resort, with sauna, steam, cold plunge and thermal pools in North Beach.

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.

Istanbul

A working Ottoman hammam built in 1741 in Istanbul's Fatih district, offering traditional bath rituals with no day-pass option, only full treatments.

Medellín, Antioquia

Day spa in a rooftop wellness area at the Celestino Hotel in El Poblado, with sauna, steam room, jacuzzi, cold plunge and massage treatments.

Marrakech, Marrakesh-Safi

A 1,200-square-metre hotel spa at Selman Marrakech built around the Chenot method, with hammams, pools and multi-day wellness programmes.

Hot Springs, Arkansas

A combined day spa and med spa in Hot Springs offering massages, facials, laser treatments and lunch-inclusive packages by reservation.

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.

Hot Springs, Arkansas

Day spa and Aveda salon in Hot Springs with baths, a salt room, oxygen bar and massage, facial and hair services.

Durango, Colorado

A hot springs resort in the Animas Valley near Durango, Colorado, with 32 mineral pools, cold plunges, a lap pool and private cedar soaking tubs.

Palm Springs, California

Moroccan-themed inn in Desert Hot Springs with natural mineral hot springs, a spring-fed pool and day-pass access from 9am to 4pm.

Charleston, South Carolina

A West Ashley day spa in Charleston offering lymphatic massage, infrared sauna, halo therapy and foot soaks by reservation, no day pass.

Denver, Colorado

Downtown Denver massage studio with 22 treatments, cold plunge and sauna, built for membership-based regular visits rather than one-off day passes.

Portland, Oregon

A reservation-only float spa in Northwest Portland offering private suites for flotation therapy, sauna and cold plunge, with no walk-ins or day passes.

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.