Western Pacific Marathon, Half Marathon, 10K & 5K

Saturday, April 22, 2023 • Fremont, CACourse Map

Made up mostly of water thanks to the two large lakes that lie in the middle of its more than 530 acres here in the South Bay section of the San Francisco Bay Area, Fremont’s Quarry Lakes Regional Recreation Area plays host to the annual Western Pacific Marathon, Half Marathon, 10K and 5K races, along the gravel and fire trail pathways that wind through the park.

Hosted by the locally-based race management group Brazen Racing — which also organizes races like January’s Coyote Hills Half Marathon and the Bay Breeze Half Marathon in February — the race is set to feature a smaller size field of just a few hundred runners, and a course that offers gorgeous scenery through some of the Bay Area’s natural treasures.

The race is called the Western Pacific thanks in large part to the original purpose for the quarries that served as the source for gravel back in the mid-1800s for the construction of the transcontinental railroad. Today, those quarries now have been filled in as the two main lakes inside the park, covering an estimated 350 of the park’s nearly 540 acres.

Fishing, biking, hiking, walking, running, swimming and boating are all popular outdoor activities in the park these days, thanks to the miles of trails inside the park as well as its connection to the Alameda Creek Regional Trail, which stretches from Niles Canyon in the west to Coyote Hills, and then eastward up to the Don Edwards National Wildlife Refuge on the bay.

Runners in the full, 26.2-mile marathon and the 13.1-mile half marathon will run long stretches of their routes along the Alameda Creek Trail, organizers add.

And thanks to its location near the waterfront, there are really no hills to speak of, so with a forgiving surface and flat terrain, that means personal record times are possible for runners looking to set them.

Also, the event is open to walkers as well as runners, and even to hikers, organizers say.

Race Weather & Climate

Located along the southeastern shore of San Francisco Bay, roughly 40 miles from downtown San Francisco and about 18 miles north of San Jose, Fremont typically experiences mild to moderately warm weather in April, when conditions also are usually much drier than in the winter.

On race day (Apr. 22), the average low is 51ºF and the average high is 70ºF.

Past Results

Course Map

See the race route map for the Western Pacific Half Marathon here.

Starting Time

  • 7:30 AM – full marathon
  • 8:00 AM – half marathon
  • 8:30 AM – 10K
  • 8:45 AM – 5K


  • $70 – $80 for the half marathon
  • $88 – $98 for the full marathon
  • $54 – $64 for the 10K
  • $47 – $57 for the 5K
  • Note: all participants may elect not to receive a shirt, saving $5


To reserve your spot in the 2023 running of Fremont’s Western Pacific Marathon, Half Marathon, 10K or 5K race, register online at RaceRoster.com here.

Official Race Website



Ever run in the Western Pacific Half Marathon? Share your impressions here, or post your review in the Comments below.

See more races in: April, California

2 comments… add one
  • Lan Chin January 26, 2023, 10:21 pm

    Is there a cut-off time limit for the half marathon? Thanks!

  • Gary Moses April 29, 2015, 12:44 pm

    Hello, my name is Gary Moses and wanted to see if your organization offers gender specific shirts to the participants in all your events. Thank you so much.


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