Bad Bass - Castro Valley

Bad Bass is an annual running event held at the scenic Lake Chabot Marina in Castro Valley, California. Scheduled for July 19, 2025, it offers three race distances: a 5K, 10K, and a half marathon. The 5K is a paved course, while the 10K and half marathon take runners through beautiful trail routes around Lake Chabot.

The event features a fun and quirky mascot—a kilt-wearing, bagpipe-playing Scottish bass fish—adding a unique atmosphere to the race. Participants enjoy well-organized races with volunteer support, awards, and race photos, making it a popular choice for runners seeking a scenic and spirited challenge in the San Francisco Bay Area. Visit the organization's website for the most recent information.