Spas with reservation required

Miami, Florida

Nature-themed day spa in Brickell with hydro massage, a hydrotherapy circuit and couples treatments, open daily 9am-6pm.

Chicago, Illinois

Hotel spa on the lower level of the Fairmont Chicago, open to guests for massages, facials and a couples suite with an infinity-edge soaking tub.

Philadelphia, Pennsylvania

Northeast Philadelphia day spa on Castor Avenue focused on skin treatments, massage and Venus Legacy body contouring, with sauna, steam and a thermal pool.

Indianapolis, Indiana

Day spa in Allisonville, Indianapolis with sauna, steam room, thermal pool and cold plunge, plus about 10 massage and facial treatments for solo visits or

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.

Miami, Florida

An upscale day spa on Miracle Mile in Coral Gables with sauna, steam room and cold plunge, known for a $200 signature treatment and couples packages.

Napa Valley, California

A family-run day spa in Vacaville near Napa Valley, offering massage, facials, waxing and a private whirlpool tub by appointment only since 1997.

Macomb County, Michigan

A budget-friendly day spa in Shelby Township, MI offering facials, body sculpting and a sauna, steam room and thermal pool for adults.

Scottsdale, Arizona

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

Port Douglas, Queensland

Day spa in Port Douglas with sauna, steam room, thermal pools and cold plunge, offering massages, facials and body treatments by appointment.

San Francisco, California

Hotel spa at The Huntington Hotel on Nob Hill with a heated soaking pool, sauna, steam room and terrace, open daily 8am-7pm; treatment booking required.

San Francisco, California

Neighborhood day spa in Noe Valley with a private outdoor hot tub, offering massage and a combined soak-and-massage package for two.

Denver, Colorado

A Whittier day spa in Denver where private suites pair beer and wine baths with infrared saunas and a self-pour taproom.

Denver, Colorado

A Littleton day spa centered on private suites with beer and wine baths, infrared sauna, zero-gravity massage and a self-pour taproom.

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.

Austin, Texas

Eco-friendly day spa in Anderson Mill, Austin, offering organic massage, facials and body treatments with a sauna, steam room and cold plunge.

Hudson, New York

Adults-only communal thermal baths and steam room in downtown Hudson, NY, with day passes, memberships and treatment-plus-soak packages.

Shibu Onsen, Nagano

Reservation-only private hot spring and sauna suites at a Nagano brewery complex, built around a craft beer bathing plan for two to four guests.

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.

Naples, Florida

Luxury day spa in Central Naples offering massage, facials and combination packages, including a $420 signature ritual, with couples treatments by reservation.

Aspen, Colorado

Adults-only hotel spa at The St. Regis Aspen with Thai-inspired massage, 111Skin facials, an AI robotic massage, and a day pass covering pool, cold plunge, and

Scottsdale, Arizona

Recovery-focused studio in South Scottsdale centered on a cold plunge, hot tub, infrared sauna, compression therapy and red light rooms rather than traditional

San Francisco, California

A reservation-only day spa in San Francisco's Marina offering private cold-plunge-and-sauna contrast suites and quiet float sessions, no walk-ins.

Charleston, South Carolina

A Mount Pleasant recovery studio near Charleston offering cryotherapy, compression therapy and infrared sauna sessions, open daily except Sunday.