17600 Lake Chabot Road, Castro Valley CA
Saturday, July 18th, 2026
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 on July 18th 2026! Why is he Scottish? What is he doing in Castro Valley? How can he play bagpipes with his fin? We have no idea how to answer those questions. 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!
Gear up for your ultra
What runners rely on for long days on their feet.
Top pick
SWIFTVEST Running Vest for Women & Men with Water Bottle | Lightweight Hydration Vest | Reflective Running Gear | Adjustable Fit | 6 Pockets | Phone Holder for Runners
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Garmin Forerunner 55, GPS Running Watch with Daily Suggested Workouts, Up to 2 Weeks of Battery Life, Black - 010-02562-00
$164.99
SHOKZ OpenRun Bone Conduction Open-Ear Bluetooth Sport Headphones, Running Workout Bundle with Waterproof Carrying Case & Sweat Headband, IP67 Sweat Resistant, 8H Playtime, Mic, Black
$129.95
Venture Pal Chewable Electrolyte Tablets, 80 Count Fast-Dissolve Sugar-Free Stick Salt Tablets,Gluten Free – Variety Pack for Rapid Hydration, Outdoor Running, Hiking | Keto & Vegan Friendly | 4 Pack
$16.79
LHKNL Headlamp Flashlight, Lumen Ultra-Light Bright LED Rechargeable Headlight with White Red Light, 2-Pack Waterproof Motion Sensor Head Lamp,8 Modes for Outdoor Camping Running Hiking Fishing
$19.99
GADIEMKENSD Quick Drying Running Hat Summer Cooling Baseball Cap UPF50+ Sports Sun Caps Breathable Mesh Lightweigh Dad Hats Unstructured for Golf Workout Hiking Gym Travel Camp Pink S/M 6 7/8-7 1/4
$13.99
Course Map
Train for this race
Find a local run club
Run clubs in Castro Valley, CA host weekly group runs — a great way to prep for race day.
