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Bad Bass Half Marathon/10K/5K

Quick facts

Distance Half marathon

About Bad Bass Half Marathon/10K/5K

Rising up from the depths of Lake Chabot, the Bad Bass (a strangely kilt-wearing, bagpipe-playing Scottish bass with teeth) shows itself once again in this year’s race! Why is he Scottish? What is he doing in Castro Valley? How can he play bagpipes with his fin? Why is he so bad-to-the-fishbone? Maybe he just knows how awesome the trails of Lake Chabot really are!

Whatever the Bad Bass is doing here, we hope you’ll join us at the beautiful Lake Chabot Marina in Castro Valley for the scenic Bad Bass 5K, 10K or Half Marathon!

Beginning and ending at the Lake Chabot Marina, the courses includes rolling, but mostly runnable hills. The half marathon is roughly 50% on paved trail and 50% on fire trails. Whether you are an experienced trail runner or a first-timer ready to get your feet dirty, there’s a lot to like about this race!


Half Marathon

  • 21.1km


  • 10km


  • 5km


Aid Stations

The half marathon will have 4 aid stations. Aid stations will be fully stocked with water, sports drink, gels, pretzels, candy, etc.

Award Medals

All finishers will receive custom finisher medals and custom shirts. Age group awards will be awarded to the top 3 finishers in 5 year categories (less for the younger ages).

Maximum Time

4.5 hours.

Bad Bass Half Marathon/10K/5K Route Map

Bad Bass Half Marathon/10K/5K Route Map


Lake Chabot Marina

Lake Chabot,us




Lake Chalbot, which doubles both as a drinking water reservoir for the East Bay area and as a recreational park, filled with more than 20 miles of hiking trails as well as the 315-acre lake that draws visitors year-round for fishing and boating, is visible along the course.


All three races in the event start and finish at the Lake Chalbot Marina, which lies at the southernmost tip of the lake just off Fairmont Drive.

From there, runners in the half marathon follow a counter-clockwise out-and-back loop route that takes them first northward around the eastern side of the lake, along which runners can expect both paved trails and later natural trails through the woods along the lakeshore.

(Organizers say that over the course of the half marathon, the surface is roughly half paved and half natural trails.)

While the first couple miles of the half marathon course are mostly flat, runners can expect the course to turn hilly between the 2nd and 3rd mile markers as the route heads into the fire trails and hills around the eastern side of the lake.

The hilly stretches continue for roughly the next five to six miles, after which the route descends from the hills around the lake back onto the trails that hug closer to the lake’s shoreline, and bring runners back in to the marina for the finish line.

The race information has been found on the official website of the event or through publicly available sources. Always refer to the official website the latest race information. Please let us know if any data is wrong or missing, by emailing us.