The park's swimming lagoon is formed by an earthen dam built in the 1960s to create a reservoir for flood control and recreation.
The site hosts a unique 'trout derby' tradition for youth anglers during the winter stocking season.
The park provides direct access to the San Lorenzo Creek corridor, a vital riparian habitat in the suburban landscape.
Geologically, the park lies near the Hayward Fault, which influenced the local topography and creek alignment.
Don Castro Regional Recreation Area is a 101-acre park centered around a lagoon created by damming San Lorenzo Creek. The park features a sandy swimming beach, which is typically staffed by lifeguards during the summer season. The recreation area is integrated into the East Bay Regional Park District trail network, offering access to hiking and equestrian paths. The lagoon is stocked with rainbow trout during the cooler months to support recreational fishing. Wildlife observers can spot various bird species around the water, including herons and egrets. The park includes designated lawn areas for picnics and dispersed shaded zones near the water. It serves as a connector to the Castro Valley Trail, providing multi-use access to surrounding natural corridors.
The pedestrian bridge overlooking the dam spillway offers the widest panoramic view of the lagoon and surrounding riparian forest.
Check the East Bay Regional Park District website for seasonal water quality updates before planning a swim.
Bring a fishing license if you intend to fish, as state regulations are strictly enforced.
Use the upper meadow areas for picnicking to avoid the higher foot traffic found directly at the beach.
Do not swim in the lagoon outside of the designated lifeguard-patrolled season or in areas marked as restricted, as water conditions change based on runoff.
Lifeguard services at the swimming lagoon are seasonal; swimming is typically prohibited when lifeguards are not on duty.
No dogs allowed on the swimming beach; all pets must be leashed in developed areas. Pack out all trash to preserve local wildlife habitats.
