Pool at Fairmont Sonoma Mission Inn in Sonoma County
Fairmont Mission Inn & Spa

Hot Springs in Sonoma County

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Geothermal mineral springs-often called hot springs-are a fabulous wellness attribute of Sonoma County. The Geysers area in Northern Sonoma County represents part of the largest geothermal field in the world. Hot mineral springs, which exist around the world, are produced when geothermally-heated and mineralized groundwater emerges from the earth to form pools of water ranging from warmish to scalding.

Most people enjoy springs that hit a sweet spot somewhere between warm and hot-the point at which water relaxes mind and body, soothes aching joints, and introduces a feeling of bliss.

For centuries, Sonoma County's geothermal springs attracted Native Americans from the surrounding region and well beyond; many tribes considered certain springs to be sacred, and they would travel for days to immerse themselves in the waters. 

Today, you can still enjoy three of Sonoma County's most legendary hot springs: Boyes Hot Springs, Morton's Hot Springs, and Agua Caliente.

Fairmont Sonoma Mission Inn & Spa, Boyes Hot Springs

The pool at the Fairmont Sonoma Mission Inn & Spa surrounded by palm trees
Fairmont Sonoma Mission Inn & Spa

The thermal waters of Boyes Hot Springs come in a luxurious setting at the Fairmont Sonoma Mission Inn & Spa.

Originally built in 1927 in the style of California's early missions, the property was renovated in the late 20th century. Shortly thereafter, a new thermal mineral water source was discovered more than 1,000 feet below the hotel.

The waters of Boyes Hot Springs can be enjoyed in the pools and hot tub at the Inn's Willow Stream Spa. Water temperature varies from pool to pool. The Watsu pool is kept at body temperature; the indoor spa is somewhat warmer; and the spa's main pool hovers around 85° (but the main pool is open to hotel guests only).

Except for the main pool, a spa day pass to use the bathhouse area is $89; this fee is waived for non-hotel guests who schedule one or more same-day body, facial, and/or salon treatments. Open year-round.

Sonoma Aquatic Club, Agua Caliente

When you dip into a pool at the Sonoma Aquatic Club in Agua Caliente, you join a tradition that dates back countless centuries: hanging out, for recreational or curative purposes, in these soothing thermal mineral waters. The hot springs here were reputed to be so curative that distant tribes traveled days to bathe in them. 

You'll find three pools: an Olympic-sized outdoor pool, with 25-yard and 50-meter courses, as well as lap swimming and recreational swimming; an indoor 90° pool; and an outdoor covered 102° spa with lots of jets at many levels. All water comes directly from the natural hot springs below ground.

There's also a workout room with treadmills, elliptical machines, stationary bikes, a Stairmaster, and weights. In-pool classes include water yoga, aqua aerobics, and an adult swim clinic. The Aquatic Club offers individual and family memberships, but visitors can arrange for a one-day visit.

Morton's Warm Springs, Glen Ellen

People swim in the pool at Morton's Warm Springs in Sonoma County
Morton's Warm Springs

Nestled into a bucolic setting of oak forested hills and a lively creek, the 20-acre Morton's Warm Springs is located about four miles from Glen Ellen's village center. Its historic geothermal mineral springs, once sacred to the local indigenous tribes, remain accessible today in three mineral spring pools.

Temperatures average between 85-88° and depths are 1-9 feet, with lifeguards on duty. Comfortable chaises and benches surround the pools, and there's also a large lawn area with picnic and barbecue sites and an organic café. While there you can walk around Morton's extensive grounds, which include heritage oaks, more than a third of a mile of Sonoma Creek, and spots where the artesian warm springs still bubble forth.

Morton's is open to the public through memberships, group reservations, and general admission access from May through September.

Looking for more fun things to do during your trip to Sonoma County, or are you trying to figure out where to stay during your vacation? Take a look at the many outdoor activities to enjoy in the valleys, vineyards, coastline and Russian River areas of Sonoma County.

Written by Sonoma Insider Suzie Rodriguez.