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 produced when geothermally heated and mineralized groundwater emerges from the earth to form pools of water ranging from warmish to scalding. Hot springs are one of the most fabulous aspects of Sonoma County's landscape, inviting opportunities for wellness and outdoor exploration. 

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—from Petaluma in the south to the sprawling Geysers field in the north—attracted Native Americans from surrounding regions and well beyond. Many tribes considered some of the area's springs to be sacred, and would travel for days to immerse themselves in the waters. 

Today, visitors can still enjoy three of Sonoma County's most legendary hot springs, all in the Sonoma Valley: 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 year-round 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°. 

These geothermal pools are open to guests and non-guests of the hotel for various fees; check the spa's website for more details.

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. Use of the indoor pool requires reservations, but use of the outdoor pool and spa does not; check the club's website for more details. 

Morton's Warm Springs, Glen Ellen

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

About four miles from Glen Ellen's village center,  the 20-acre grounds of Morton's Warm Springs resort include heritage oaks, almost half a mile's worth of Sonoma Creek, and three bubbling pools of mineral springs. Morton's is open May through September, and for both members and general-admission visitors, reservations are required.  

Water temperatures here average between 85-88°, depths are 1-9 feet, and lifeguards are on duty. Comfortable, socially-distanced chaises and benches surround the pools, and there's also a large lawn area with picnic and barbecue sites, as well as an organic café.

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.