Spas with reservation required

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.

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.

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.

Los Angeles, California

A women-focused Korean day spa in Pico-Union with steam, salt and ice rooms, open daily 9am to 9pm, with massage and facials open to men too.

Scottsdale, Arizona

North Scottsdale day spa with massage, facials, sauna, steam and a thermal pool, plus private suites for couples and groups.

Park City, Utah

A 14-room hotel spa at Westgate Park City Resort with a waterfall, sauna, steam room and thermal pools, open daily 9:30am-6:30pm.

Cincinnati, Ohio

Day spa in Columbia-Tusculum, Cincinnati, with massage, facials, an infrared/Himalayan salt sauna and a $99 signature sampler package.

Napa Valley, California

Hotel day spa atop the Archer in downtown Napa with a water deck, fitness studio access and treatment rooms; reservations required.

Milford, Ohio

A small, adults-only day spa in Historic Old Milford with a salt room, massage room and red light therapy, booked by reservation.

Indianapolis, Indiana

A moderate-priced day spa in northwest Indianapolis offering float therapy, salt room sessions, infrared sauna, cold plunge and foot detox, closed Mondays.

Las Vegas, Nevada

Adults-only hotel spa inside Westgate Las Vegas offering massages, facials, salon services, sauna, steam room and a thermal pool, open daily 9am-6pm.

Santa Barbara, California

A downtown Santa Barbara day spa built around a private infrared sauna, salt room, cold plunge and a sound-and-light meditation pod, booked by appointment.

Los Angeles, California

A Westlake day spa built around themed sauna rooms—salt, gold, Loess soil, Elvan stone, forest and ice—plus a waterfall feature and garden.

Palm Springs, California

Hotel spa at Agua Caliente Rancho Mirage with day passes for the sauna, steam room, salt rooms and private spa pool.

Los Angeles, California

A Silver Lake day spa with 20 treatments, Thai massage, acupuncture and a salt-infused infrared sauna, open daily 10am-9pm.

Marana, Arizona

Adults-only hotel spa at Dove Mountain Resort in Marana with desert-themed treatments, an infinity-edge pool, sauna and steam room; facility access comes with

Scottsdale, Arizona

Resort spa at Camelback Inn in Scottsdale with 20 treatment rooms, a thermal circuit and day-pass access open to non-guests.

Tucson, Arizona

Six-room hotel spa at Hacienda del Sol in Tucson, open daily 9-6, taking both resort guests and local walk-ins for massages, facials and body treatments.

San Diego, California

Resort spa on Mission Bay offering massages, facials and body treatments, with walk-ins welcome and a gym and yoga classes on-site.

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+.

Scottsdale, Arizona

Adults-only hotel spa at the Fairmont Scottsdale Princess with a rooftop pool, grotto waterfall pool, sauna, steam room and cold plunge, open daily 6am-7pm.

Houston, Texas

Luxury day spa near Houston's Galleria with massage, facial and body treatments, a salt room and infrared sauna; reservations only, no walk-ins.