Spas with reservation required

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.

Fallston, Maryland

A Fallston, Maryland day spa specializing in Japanese head spa treatments, serum infusion facials, dermaplaning and body contouring, with walk-ins accepted.

Boston, Massachusetts

A Finnish kelo-log banya in Newton with sauna, steam room and cold plunge, alternating men's and women's days, day passes from $69.

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.

Scottsdale, Arizona

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

Palm Springs, California

A no-frills, family-run day spa on Indian Canyon Dr offering walk-in massage and foot reflexology from $40, open daily until 10pm.

Palm Springs, California

Adults-only hotel spa at the Parker Palm Springs with 15 private treatment rooms, couples suites and a $300 signature aloe treatment.

Birmingham, Michigan

A Birmingham, Michigan day spa built around waterless volcanic rock treatments, with V-steam, facials, massage and a steam room for adults and couples.

Seattle, Washington

An adults-only wellness studio near Green Lake with private infrared sauna suites, therapeutic massage and red light therapy by reservation.

Sedona, Arizona

A moderately priced day spa in Sedona with outdoor gardens, a hot tub and fountains, known for its Prickly Pear Pomegranate body treatment.

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.

Sedona, Arizona

Adults-only resort spa in Sedona with outdoor hot tubs, steam rooms and a 30-treatment menu, open daily with walk-ins and day passes.

Chicago, Illinois

A moderately priced day spa in Chicago's Lakeview neighborhood focused on Chinese-style head and scalp treatments, open to adults 16 and up.

San Francisco, California

Oakland float and sauna studio near Grand Lake with private float tanks, infrared sauna cocoons and cryotherapy, open daily 11am-8:30pm.

Rocky River, Ohio

Massage-focused day spa in Rocky River offering couples treatments, sauna, steam room and thermal pool, open daily by appointment.

Elkridge, Maryland

A halotherapy day spa in West Elkridge, near Baltimore, built around a salt cave, massage rooms and a yoga studio, aimed at solo adult visitors.

Palm Springs, California

Downtown Palm Springs day spa built around a natural hot mineral spring, with private mineral baths, sauna, steam room and massage.

Springboro, Ohio

A wellness center in Springboro, Ohio built around a natural salt cave, with energy healing, sound baths and metaphysical classes for individuals or groups.

Los Angeles, California

Day spa in a Montebello strip mall plaza offering facials, massages and body treatments, open daily with walk-ins accepted.

Transylvania County, North Carolina

All-inclusive multi-night wellness retreat in Pisgah Forest, NC, combining fitness classes, spa treatments, guided hikes and farm-to-table meals in private

San Francisco, California

A reservation-only day spa on El Camino Real in San Bruno specializing in head spa therapy, scalp care and lash services for adults.

Des Peres, Missouri

A moderate-priced day spa in Des Peres, just west of St. Louis, open six days a week with a relaxation lounge and treatments geared toward couples and adults.

Texas Hill Country, Texas

A medical spa on San Antonio's Far West Side offering massage, facials, injectables and laser hair removal, open weekdays and Saturday mornings.