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Sun September 7, 2025 Clayton, CA 94517 US Directions
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Events

4 Mi

$54 $43.40 incl. $3.40 Fee 8:15AM PDT
63 spots left. Price increases after August 31, 2025 at 11:59pm PDT

10 Mi

$64.60 $54 incl. $4 Fee 8:00AM PDT
45 spots left. Price increases after August 31, 2025 at 11:59pm PDT

Half Marathon

$75.20 $64.60 incl. $4.60 Fee 8:00AM PDT
106 spots left. Price increases after August 31, 2025 at 11:59pm PDT

Marathon

$85.80 $75.20 incl. $5.20 Fee 8:00AM PDT
19 spots left. Price increases after August 31, 2025 at 11:59pm PDT

50K

$96.40 $85.80 incl. $5.80 Fee 8:00AM PDT
39 spots left. Price increases after August 31, 2025 at 11:59pm PDT

Kid's Run (6yo & younger, 50yd dash) - Free!

$0 7:50AM PDT Registration ends September 7, 2025 at 7:55am PDT

Place

Diablo State Park (Mitchell Canyon Trailhead)
96 Mitchell Canyon Road
Clayton, CA US 94517

Description

Mount Diablo provides spectacular views of the San Francisco Bay Area and surrounding valleys.  The 4 mile course is relatively flat and fast within Mitchell Canyon.  The longer events are mountainous and very scenic.
(Distances are accurately measured using a Rolatape® surveyor's measuring wheel.)

Bib Number & Shirt Pick-up

Race Day: Check-in beginning at 7:00 a.m. at Mt. Diablo State Park (Mitchell Canyon Trailhead). Please arrive 45min before your event to receive your bib and shirt. Event start times are listed here.
Parking is $6 per vehicle. Please bring exact change to expedite entry.
Drop Bags: You can leave a drop bag with non-valuables at the Start/Finish.

Time Limit & Cut-off

Marathon - 9 hours (3 hrs, 11:00 a.m. @ 9 mi)
50K - 9 hours (2 hrs 45 min, 10:45 a.m. @ 9 mi; 6 hrs 35 min, 2:35 p.m. @ 21 mi)
All Events - 9 hours

Course

The course will be marked with ribbon approximately every 200 yards and color coded as follows:

4 mi – Yellow
10 mi – Orange (turnaround @ 1st Aid Station)
Half Marathon – Orange (turnaround @ Summit)
Marathon – Orange + Green Summit Loop + Pink Loop + Orange to Finish
50K - Orange + Green Summit Loop + Pink Loop + Green Summit Loop (on return @ 21 mi) + Orange to Finish

The most important course marking is the polka-dot flagging. It indicates a turn at an intersection. There will be at least two polka-dot flagging before a turn in the course. The polka-dot flagging will be placed before and on the same side as the required turn. As you approach an intersection, look for any polka-dot flagging before the turn. Waiting until you're in the intersection to determine the correct direction may be confusing and you may go the wrong way. After you complete the turn, there will be yellow, and/or pink flagging indicating the correct route. We also hang blue ribbons at critical junctions indicating the wrong way. Blue is bad!

If you don't see your respective flagging for 3-4 minutes, you are off course. If you get off course, you should retrace your path until you find where you left the course and then continue along the marked course.

Please be courteous on the trail. If you're passing another runner or hiker, announce "on your left" as you approach.

Headphones are allowed on dirt road sections only. Please do not wear headphones on single-track trail, while crossing paved roads, when getting aid at aid stations, or while crossing the finish line.

Your bib number indicates the distance that you're running. If you want to change your distance, please send us an e-mail or let us know by check-in, at the latest.

Many of the parks in California have poison oak. We recommend staying on the trail and washing with Tecnu after your trail run. Occasionally, bees or yellow jackets may be active and precautions should be taken if you're allergic.

No dogs allowed on the course. Please don't leave pets in your vehicle.

GPX Files:

Click the icon below to download the attached PDF.

PDF

Elevation Profiles/Course Surface

4 mi

Elevation Gain: 400'
Course Surface: Single Track (0%), Dirt Road (100%), Asphalt (0%)

 

 

10 mi

Elevation Gain: 2,420'
Course Surface: Single Track (0%), Dirt Road (100%), Asphalt (0%)

 

 

Half Marathon

Elevation Gain: 3,420'
Course Surface: Single Track (21%), Dirt Road (76%), Asphalt (3%)

 

 

Marathon

Elevation Gain: 6,760'
Course Surface: Single Track (28%), Dirt Road (70%), Asphalt (2%)

 

 

50K

Elevation Gain: 8,000'
Course Surface: Single Track (38%), Dirt Road (60%), Asphalt (2%)

Aid Stations

Fully-stocked aid stations every 3 - 5 miles. You can expect fresh fruit, salty snacks, assorted candy, water, and Skratch electrolyte sports drink. It is highly recommended that runners carry at least 20 oz. of water between aid stations.

Click the icon below to download the attached PDF.

PDF

Cupless

In an effort to reduce waste and litter, Coastal/Zoom events are cupless. We request that you bring your preferred means of containing fluids during your run and at the aid stations. We will have some Hydrapak SpeedCup ($5) for sale at check-in.

Please note that there are no pre-filled cups of hydration at the aid stations. In case you really need a disposable cup, please request one from the aid station volunteers. We ask that you use only one. Thank you!

Results

We use state-of-the-art Bibtags by MyLaps to accurately time each runner’s finish time. Results are published on the website every 30 minutes.

Awards

T-shirts will be given to all pre-registered runners. All finishers will receive a custom medal and 50K finishers will also receive a custom coaster.

Overall Winners: The top 3 male and female overall winners of every distance will win an award and race credits to future Coastal races:

1st Place - $50
2nd Place - $35
3rd Place - $20
 

These race credits are valid for 3 months from date of issue and is for one time use only.

Top three finishers in each age group and gender will receive award medals.

Note: Overall and age group placing are based on Clock Time rather than Chip Time.  As a bona fide competition, runners should start at the same time and compete against each other on the course.  Chip Time is used so runners can see their actual elapsed time.

Course Records

4 mi
  Cory Munsch, 27, San Francisco, CA ('22)  23:58
  Amy Crain, 44, Walnut Creek, CA ('22)        27:51
10 mi
  Anthony Munch, 38, Concord, CA ('16)     1:24:38
  Tori Tyler, 26, Danville, CA ('13)                1:27:22
Half Marathon
  David Roche, 26, Sunnyvale, CA ('14)      1:39:18
  Megan Roche, 24, Sunnyvale, CA ('14)    1:48:14
Marathon
  Chris Castleman, 28, San Bruno, CA ('15)  4:02:52
  Rea Kolbl, 24, Stanford, CA ('15)                4:13:04
50K
  Jonathan Gunderson, 33, San Francisco, CA ('11)  4:52:39
  Sarah Lavender Smith, 41, Piedmont, CA ('10)       5:31:21
 

Gallery

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