Spas with upscale

Lake Tahoe, California

An adults-only hotel spa at the Everline resort in Olympic Valley, open to day visitors and hotel guests Thursday through Sunday.

Asheville, North Carolina

A reservation-only, adults-only spa inside Grand Bohemian Lodge in Biltmore Village, open to hotel guests only.

Orlando, Florida

A hotel spa inside the Hyatt Regency Orlando conference hotel on International Drive, open daily for guests only.

Napa Valley, California

Adults-only resort spa in Napa Valley with pools, sauna, steam and a fitness center, open to hotel guests and club members via day pass.

Scottsdale, Arizona

Adults-only resort spa inside Talking Stick Resort in Scottsdale, open daily with couples-friendly treatment rooms and day-pass access for hotel guests.

Houston, Texas

Thompson Spa is a hotel spa in Houston's Fourth Ward open only to hotel guests, with reservations required and an adults-only, couples-friendly setting.

Washington, D.C., District of Columbia

A hotel spa inside the Waldorf Astoria on Pennsylvania Avenue NW, open daily with adults-only access and both day-pass and guest-only policies listed.

Atlanta, Georgia

An adults-only hotel spa in Buckhead with private treatment suites and a relaxation lounge, open daily with a day-pass option.

Buxton, England

A hotel spa built into Buxton's historic Crescent, centred on a thermal pool, hydrotherapy circuit and salt room, open to hotel guests only.

Velingrad, Pazardzhik

Adults-only hotel spa in Velingrad with a mineral-water pool, jacuzzi and massage pool, open to overnight guests of the five-star Kashmir property.

Karlovy Vary, Karlovy Vary Region

Adults-only resort spa on the Březová reservoir near Karlovy Vary, open to hotel guests only, with a two-floor wellness centre and outdoor baths.

Miami, Florida

A hotel spa at Eden Roc Miami Beach in Mid-Beach with sauna, steam room, cold plunge and thermal circuits, open to resort guests only.

Punta Cana, La Altagracia

A hotel spa inside the adults-only JOIA Bávaro by Iberostar beach resort in Punta Cana, open only to overnight guests.

Spa, Liège

Hotel spa in the town of Spa, Belgium, with a thermal pool, relaxation lounge and restaurant, open to day-pass visitors, not just hotel guests.

Kyle, Texas

A 88-acre Hill Country resort near Kyle and Wimberley with overnight rooms, a garden spa, pool, hot tubs and day-pass access by reservation.

Park City, Utah

Serenity Spa is the treatment center inside Westgate Park City Resort, a ski-in villa resort with a year-round indoor/outdoor pool, sauna and steam room for

Nashville, Tennessee

Adults-only hotel spa at the Conrad Nashville in Midtown, open to hotel guests and available by day pass at an upscale price point.

Catskills, New York

Adults-only resort spa in the Catskills with sauna, hot tub, yoga studio and overnight stays for hotel guests only.

Huntington Beach, California

An adults-only hydrotherapy circuit with hot tub, sauna and steam room for guests staying at this beachfront Hyatt Regency resort in Huntington Beach.

Boston, Massachusetts

Hotel spa inside the InterContinental Boston in the Downtown waterfront area, open to hotel guests only.

San Antonio, Texas

An adults-only hotel spa inside the InterContinental San Antonio Riverwalk downtown, open to hotel guests and day-pass visitors.

Hudson Valley, New York

Hotel spa inside a restored convent in Peekskill, overlooking the Hudson River, open only to overnight guests of The Abbey Inn.

Las Vegas, Nevada

A hotel spa at the Westin Las Vegas on Flamingo Road, limited to hotel guests and adults only.

Tulum, Quintana Roo

Beachfront resort in Tulum pairing overnight stays with spa treatments, yoga and fitness classes, open to hotel guests only.