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.

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.

Chicago, Illinois

Hyde Park day spa since 1978 offering facials, massage, body treatments, waxing and hydrotherapy, with walk-ins welcome.

Plainfield, Indiana

Day spa in Plainfield, IN offering facials, massages and body-sculpting treatments alongside a sauna, steam room and thermal pool, reservation required.

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.

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.

Indianapolis, Indiana

Two Indianapolis locations for cryotherapy, infrared sauna, Normatec compression and float therapy, with walk-ins welcome.

Austin, Texas

A North Austin head spa near The Domain built around Japanese-style scalp massage, with private, couples and group suites by appointment.

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.

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.

Nashville, Tennessee

A Brentwood day spa focused entirely on scalp and head treatments, with private suites and a signature ritual built around halo water therapy.

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.

Seattle, Washington

A Bellevue day spa in Wilburton specializing in head spa scalp treatments, massage, facials and couples sessions, with free on-site parking.

Atlanta, Georgia

A reservation-only wellness center in Edgewood, Atlanta offering colon hydrotherapy, hyperbaric oxygen therapy, sauna and an oxygen bar for couples or solo

Gold Coast, Queensland

An overnight wellness retreat in Tallebudgera Valley with a cedar sauna, magnesium spa bath, ice bath and a 60-minute aromatherapy massage.