Diablo Trails Challenge

APR
4
2026
The Diablo Trails Challenge offers four trail distances on Mount Diablo. A portion of entry fees supports the conservation work of Save Mount Diablo. The half marathon is part of the challenging Brazen Ultra Half Series.
Sat 4 Apr 2026
50 kilometers Half Marathon 10 kilometers 5 kilometers

Always double-check with the organizer's website! This page may contain affiliate links.

Diablo Trails Challenge

The Diablo Trails Challenge is a trail running event on Mount Diablo organized by Brazen Racing. The event takes place on April 4, 2026.

Participants can choose from four distances:

  • 50K
  • Half Marathon
  • 10K
  • 5K

The event was created to help celebrate and support the work of Save Mount Diablo, a conservation organization. A portion of all entry fees goes to the organization to support its work preserving open space and trails. The half marathon distance is part of the Brazen Ultra Half Series, which consists of half marathons noted for significant ascents, descents, and tough trails. Visit the organization's website for the most recent information.

50 km
50k
Half Marathon
Half Marathon (ultra Half Series)
10 km
10k
5 km