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.

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.

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.

Asheville, North Carolina

A therapist-owned day spa near downtown Asheville offering massage, bodywork, a private sauna and foot soaks by appointment, with free parking.

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.

Miami, Florida

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

Hong Kong

Hotel spa on the 41st floor of the Cordis in Mong Kok, with a day pass covering pool, sauna, steam room and onsen shower for HK$500.

Los Angeles, California

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

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.

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.

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.

Fishers, Indiana

A recovery-focused studio in Fishers offering whole body cryotherapy, cold plunge, infrared sauna and compression therapy on a day-pass or single-visit basis.

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.

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.

Bishop, California

A century-old natural hot springs pool near Bishop in the Eastern Sierra, with a cooling waterfall, a separate hot soak, and simple day-use facilities.

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.

Portland, Oregon

Day spa on McMenamins' Edgefield estate in Troutdale offering massage, nails, body treatments and a heated saltwater soaking pool, 18+.

Austin, Texas

Hotel spa at Omni Barton Creek with steam room, sauna, cold plunge and a rooftop pool overlooking Hill Country, open daily 9am-7pm.

Santa Fe, New Mexico

A 77-acre hot springs resort outside Santa Fe with spring-fed thermal pools, day-pass soaking packages from $175, and overnight lodging.