Monte Rio Beach is the main public swimming beach of the Monte Rio Recreation and Park District, a small special district that runs the parks in the village of Monte Rio in western Sonoma County. It is a broad gravel and sand bar on the north bank of the Russian River, just upstream (east) of the green steel Monte Rio Bridge that carries the Bohemian Highway over the river. The district describes it as the largest public beach on the lower Russian River. Locals have long called this stretch Big Rocky Beach, and it hosts the Big Rocky Games, a run of children's beach and water contests, over the Fourth of July weekend.

From Highway 101 in Santa Rosa, take River Road west through Guerneville and stay on it (it becomes Highway 116) until you reach Monte Rio. The beach entrance is beside the Monte Rio Community Center at 20488 Highway 116, at the north end of the bridge. The lower lot down on the beach opens only in the summer season and closes at 8 pm. The upper lot by the community center stays open all year, and footpaths lead from it down to the water. Sonoma County Transit buses stop on Highway 116 at Church Street, a short walk away.

The swim area is the river channel along the front of the beach, east of the bridge. The bottom is river gravel and cobble, so water shoes help. Families stay in the shallows near shore, while the channel gets deep enough to be over your head. The water is cool in late spring and warms through July and August as flows drop. There are no lifeguards. A swimmer drowned here on July 13, 2025, and the district's board reported three more near drownings that summer, all tied to people who could not swim and were not wearing life vests. The district has since added more signs and a rack of free loaner life vests on the beach. It also says swimming west of the bridge, between the bridge and the boat ramp, is not recommended.

Walking onto the beach is free, and the district says the beach is open to the public year-round. The summer season, when the lower lot, snack shack and boat rental shack operate, runs roughly from Memorial Day through Labor Day. Beach staff have at times asked drivers for a parking donation at the lower lot, but the district posts no fixed parking fee. Canoe, kayak and paddleboard rentals are paid. Alcohol and amplified sound are prohibited. Dogs belong at Sandy Beach, the leashed dog beach just west of the bridge.

Sonoma County Environmental Health samples the water here weekly between Memorial Day and Labor Day and posts the results online. The August 31, 2026 sample was within state standards and the beach was listed as open. That is not guaranteed: in July 2017 the county closed Monte Rio Beach to swimming for several days after high E. coli counts, so check the county's freshwater page before a summer visit.

The beach also has sand volleyball courts, horseshoe pits and built-in barbecues, and the district lends an all-terrain beach wheelchair free of charge by reservation at 707-865-2487. After a slow 2025 season the board discussed not reopening the snack shack, so bring your own food. Across the river from Sandy Beach, Dutch Bill Beach is a quieter family beach reached from Main Street.