When are most half marathons held in Castro Valley?
January is the busiest month for Half Marathon races in Castro Valley, with 2 of the 6. If you are flexible on the date, that is the quickest way to narrow things down.
California · Half Marathon
2026-2027 Half Marathons in Castro Valley, California
Every upcoming Half Marathon around Castro Valley, with start times, entry fees, finish-time stats from past editions, start-line maps, and the local run clubs to train with.
6 upcoming half marathons found · 5 with finish-time stats
By the numbers
The Biggest and Longest-Running
The Castro Valley races that stand out on the numbers: the biggest field, and the longest unbroken run of editions.
Sat, Nov 7, 2026Lake Chabot Trail Run Castro Valley, CAFrom $70Details Fri, Jan 1, 2027Brazen New Year's Day Castro Valley, CAFrom $100Details Fri, Jan 1, 2027Brazen New Year's Eve Castro Valley, CAFrom $100Details Sat, Apr 17, 2027SPASM Lake Chabot Trail Run Castro Valley, CAFrom $70Details Sun, Jun 6, 20272027 Lake Chabot Trail Challenge (Half Marathon & 5K) Castro Valley, CAFrom $65Details Sat, Jul 24, 2027Bad Bass Castro Valley, CAFrom $90Details
How we calculate these stats: RunSesh calculates these figures from the most recent published results of past editions, sourced from RunSignup. We show aggregates only: field size, winning and median times, and the cutoff. We never publish individual finisher tables. Last updated Oct 25, 2026.
Common Questions About Running a Half Marathon in Castro Valley
Are Castro Valley half marathons beginner-friendly?
Yes, for the most part. Across the 5 Half Marathon races in Castro Valley with published results, the typical median finish is around 2:37:28, which means half of every one of those fields came in slower than that. Recreational runners and walk-runners are the bulk of these fields, not the exception.
Where can I train for a Half Marathon in Castro Valley?
Browse Castro Valley run clubs on RunSesh to find a training group at your pace.
Are there trail Half Marathon races near Castro Valley?
Yes, 3 races around Castro Valley get you off the pavement: 3 are trail races.