Spas with reservation required

Amsterdam, North Holland

A day spa inside a former bank vault in central Amsterdam, with pool, whirlpool and a canal-view gym; adults-only, day pass by reservation.

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.

Sydney, New South Wales

Korean bathhouse in Chatswood with herbal baths, steam room and dry sauna, built around the traditional Korean body scrub, open by reservation only.

Sydney, New South Wales

Reservation-only Korean bathhouse in Paddington, Sydney, with herbal baths, a steam room and the signature Korean Body Scrub, closed Tuesdays.

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.

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.

Los Angeles, California

A day spa inside the Westin Bonaventure in Downtown LA, with massages, facials, body treatments, sauna and a relaxation lounge.

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.

Bad Füssing, Bavaria

Medical spa inside Hotel Mürz in Bad Füssing-Safferstetten, open daily 8am-7pm with walk-in day passes for facials, massage and physiotherapy.

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.

Las Vegas, Nevada

Hotel spa inside Hilton Grand Vacations on the Las Vegas Strip, open to non-guests via day pass or booked treatment, minimum age 16.

Madrid, Community of Madrid

Small Japanese-inspired onsen spa in central Madrid with a wooden hot tub, Finnish sauna and massage menu, open daily for 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.

New York City, New York

Hotel spa inside Thompson Central Park combining massages, facials and body treatments with daily fitness classes and private saunas, near Central Park.

Mauritius

Day spa in a Grand Baie residence offering massage, hammam and sauna, built around a signature foraha-oil massage and Dead Sea mineral facials.

Philadelphia, Pennsylvania

A reservation-only traditional Nordic sauna in North Philadelphia, open Wednesday through Monday and closed Tuesdays.

Bormio, Lombardy

Adults-only hotel spa near Bormio with thermal pools, a relaxation lounge and a 13-treatment menu; day passes start around €44 for evening entry.

Pagosa Springs, Colorado

A wellness lounge and day spa in Pagosa Springs offering yoga, pilates, sound baths and bodywork, with day passes and walk-in classes.

Oslo

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

Bursa

A historic thermal bathhouse and small hotel in Bursa's Kükürtlü district, with separate men's and women's hamams, day passes, and overnight stays.

Portland, Oregon

A membership-driven wellness club in downtown Portland with hot pools, sauna, steam room and cold plunge, plus massage, skincare and fitness classes.