Spas with hot tub

Napa Valley, California

Adults-only resort spa in Napa Valley with pools, sauna, steam and a fitness center, open to hotel guests and club members via day pass.

Saturnia, Tuscany

A hotel spa near Terme di Saturnia with an infinity pool, hot tub, rooftop terrace and restaurant, offering day passes for non-guests.

Calistoga, California

A 25-room Sonoma hotel in Forestville with a spa barn offering sauna, steam and pools, mainly for overnight guests.

Kyle, Texas

A 88-acre Hill Country resort near Kyle and Wimberley with overnight rooms, a garden spa, pool, hot tubs and day-pass access by reservation.

Taos, New Mexico

A moderate-priced day spa at Taos Ski Valley with a heated pool, hot tubs, steam rooms and a day pass open to non-hotel guests.

Denver, Colorado

Adults-only bathhouse on West Colfax Ave in Denver with a steam room, sauna, hot tub and relaxation lounge, open daily except Tuesday.