Bad Bass - Castro Valley

Bad Bass is a scenic running event held at Lake Chabot Marina in Castro Valley, California. Scheduled for July 19, 2025, it offers three race distances: a half marathon, 10K, and 5K. The event features a mix of paved and trail courses that showcase the beautiful surroundings of Lake Chabot.

Known for its fun and quirky mascot—a kilt-wearing, bagpipe-playing Scottish bass—the race combines a festive atmosphere with challenging terrain. Participants can enjoy well-organized races with volunteer support, awards, and race photos. The event supports the East Bay Regional Parks Campership Program, promoting outdoor recreation in the community. Visit the organization's website for the most recent information.