The Fontana Days Run is an internationally renowned race recognized by the USATF as the World's Fastest Half Marathon Course since 1985.

The Fontana Days Run is a 13.1 mile Half Marathon that starts in the San Bernardino National Forest at an elevation of 3,800 feet and drops nearly 2,500 feet to the finish line in front of Fontana City Hall. Due to the gradual downward slope of the course, many runners use the Fontana Days Run to improve their personal record or qualify for larger races.

In addition to the Half Marathon, there is a 5K Run, 5K Race Walk, 5K Family Fitness Walk and a Children's Half Mile Dash so the whole family can participate.