Spas with reservation required in 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.

A boutique day spa in downtown Napa Valley with nine treatment rooms offering massage, facials and body work, plus sauna, steam and a thermal pool.

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

A downtown Napa day spa offering massage, facials, lymphatic sculpting and sauna treatments, with walk-ins welcome and on-site parking.

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.

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

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

Hillcrest float spa offering sensory-deprivation float sessions and an oxygen bar, with walk-ins welcome but reservations required.

A reservation-based day spa in downtown Santa Barbara built around private infrared sauna, salt room and cold plunge sessions.

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

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

A Clairemont wellness studio in San Diego pairing acupuncture and bodywork with an infrared sauna and a Himalayan salt room for classes.

Day spa in Pasadena offering facials, scalp therapy and body treatments, with its signature Synergy Rejuvenation Scalp Spa, open daily 10am-7pm.

A single-room salt cave in a Carmichael strip mall offering 45-minute salt therapy sessions for relaxation and respiratory relief.

A downtown Napa day spa offering massages, facials, body treatments, waxing and nail services a short walk from the town's restaurants and hotels.

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

A Napa day spa combining massage and facial treatments with a retail shop of clean-ingredient skincare products, open by appointment six days a week.

Day spa on Lincoln Ave in Napa offering facials, massage, waxing and makeup services, open daily 9am–7pm by appointment.

A San Mateo day spa with a hot tub, open daily 10am-9pm, taking both walk-ins and reservations for couples or solo visits.

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

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

A moderately priced fitness-club spa in downtown San Francisco offering bodywork, skincare and specialty treatments with reservations required.