Spas with reservation required

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.

Day spa in the Sherry Frontenac Hotel's lower lobby in Miami Beach, with sauna, steam, cold plunge and thermal pool alongside massage treatments.

A luxury day-pass wellness circuit inside Carillon Miami Wellness Resort, with sauna, steam, cold plunge and thermal pools in North Beach.

Day spa in Sacramento's Oak Park with float rooms, private cold plunge and sauna suites, infrared sauna, and a Somadome meditation pod.

A Brentwood day spa focused entirely on scalp and head treatments, with private suites and a signature ritual built around halo water therapy.

Day spa in South Scottsdale focused on facials and a signature holistic massage, with sauna, steam room, thermal pool and cold plunge on site.

A recovery-focused studio in Fishers offering whole body cryotherapy, cold plunge, infrared sauna and compression therapy on a day-pass or single-visit basis.

A moderately priced day spa in South Scottsdale with lake-view suites, massage and facials, plus a dedicated couples treatment room.

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.

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.

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

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.

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

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

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

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

A moderate-priced day spa in Liverpool, NY, offering 20 massage-focused treatments plus sauna, steam, cold plunge and thermal pools, open daily 10am–8pm.

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

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

Hotel spa at the Inn at Eagle Mountain in Fountain Hills with sauna, steam room, pools and a $69 60-minute massage as its signature treatment.

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

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

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.

Adults-only hotel spa in downtown Napa with thermal circuits, sauna, steam and cold plunge, plus massages, facials and medical aesthetics.