Spas with reservation required

Napa Valley, California

Adults-only resort spa built into a wine cave in Napa, with a vineyard-view pool, sauna, steam room and hot tub; reservations required.

Austin, Texas

Hotel spa at Hotel Viata in West Lake Hills with treatment rooms, a couples suite, pool, sauna, steam room and a day-pass option for amenity access.

San Diego, California

Hotel spa at the historic Hotel del Coronado with an ocean-view pool, 20 treatments, and a seaweed-based signature Ocean Essence Ritual.

Seattle, Washington

Hotel spa inside the Hyatt Regency Lake Washington in Renton, offering massages, facials and body treatments alongside pool, hot tub and steam room access.

Austin, Texas

A fifth-floor hotel spa inside JW Marriott Austin with eight treatments, a heated rooftop pool and a 16-plus minimum age.

Jackson Hole, Wyoming

Resort spa at Teton Village with pools, soaking tubs, a rooftop hot tub, and facials built for Jackson Hole's dry alpine air.

Los Cabos, Baja California Sur

A hotel spa at Corazón Cabo Resort offering massages, facials and a hydrotherapy circuit with sauna, steam room and hot tub, no day passes sold.

Palm Springs, California

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

Philadelphia, Pennsylvania

Day spa in Cherry Hill Township near Philadelphia offering massage, head spa scalp treatments and couples sessions, open daily 9:30am to 9:30pm.

Miami, Florida

A 12,000-square-foot hotel spa at Coral Gables' Biltmore, with eucalyptus steam rooms, Himalayan salt saunas and a couples suite; adults-only, reservation

Port Douglas, Queensland

Ayurvedic-style massage and bathhouse studio in Port Douglas offering couples treatments, yoga and reformer Pilates, bookings required with no walk-ins.

Miami, Florida

AVEDA hotel spa at The Palms in Mid-Beach Miami, offering Ayurvedic-inspired massages, facials and salon services with pool and beach access included.

Chicago, Illinois

Luxury hotel spa in River North, Chicago, with an indoor pool, steam room and lounges, open to both hotel guests and outside bookings by reservation.

Dallas, Texas

Hotel spa in Uptown Dallas with 12 treatments, couples' rooms, separate men's and women's lounges, sauna, steam room, cold plunge and whirlpool.

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

Lake Tahoe, California

A 17-room, adults-only hotel spa at Lake Tahoe's Ritz-Carlton with a heated lap pool, sauna and steam room; day pass access requires booking a treatment.

Washington, D.C., District of Columbia

Hotel spa inside MGM National Harbor with 11 treatment rooms, sauna, jacuzzi, lounges and a full-service salon, booking required.

Scottsdale, Arizona

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

Boston, Massachusetts

Adults-only hotel spa at Encore Boston Harbor in Everett with separate men's and women's heat and water facilities, booked by appointment.

Las Vegas, Nevada

An adults-only hotel spa inside Encore Las Vegas with whirlpool, sauna and steam room, open daily for treatments and day passes, walk-ins welcome.

San Diego, California

Adults-only hotel spa in Carmel Valley with a hydrotherapy circuit, two fireplace lounges, and a $100 day pass covering pools and fitness facilities.

Austin, Texas

A hotel spa in downtown Austin with six treatments, a salt-wall relaxation lounge, eucalyptus steam rooms and a fitness center, open daily by reservation.

New York City, New York

A 30-treatment luxury hotel spa in Lower Manhattan with a lap pool, steam rooms and the German GREEN PEEL facial as its signature service.

Seattle, Washington

Hotel spa in downtown Seattle for Four Seasons guests, with a Himalayan salt wall, steam rooms and a six-treatment adults-only menu.