Spas with couples in 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.

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

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