Bouldering season is starting at Castle Rock State Park. The park sits on one of the highest ridges in the Santa Cruz Mountains, between San Jose and Santa Cruz. The San Francisco Standard calls its sandstone boulders the best bouldering in the Bay Area. It says peak season runs from late October through April, before the heat and mosquitoes arrive.

The rules that matter

  • Wet rock: The sandstone gets much more fragile when damp, and holds can break. State Parks says any measurable rain at the Kirkwood office can close climbing areas for up to three days. The Standard's advice is to wait at least 72 hours after rain.
  • No cell service: State Parks says there's no reception in or around the park and doesn't recommend rideshare. The Standard notes you won't be able to call a car to get home.
  • Fees and hours: Vehicle day use is $10 ($9 for seniors 62 and older). Day-use hours are 6 a.m. to sunset.
  • Other rules: No dogs except service animals, no drones, and no chipping, gluing or removing rock. The park's honeycombed “tafoni” formations are protected.

Where beginners should start

From the parking lot, the Standard suggests going right on Castle Rock Trail for about 10 minutes to the Magoo Boulders. It recommends starting on Magoo Warm Up, a V0 with big holds. Its starter list also includes The Groove (V1), Magoo Face (V2), The Spoon (V2), The Swim (V3) and The Beak Traverse (V3), one of the park's favorite climbs. Longtime local climber Jeremy Meigs described Castle Rock's style to the Standard as “slopey madness,” heavy on rounded holds and mantles.

What to bring

Bring climbing shoes, chalk, crash pads, water, snacks and at least one or two spotters. The Standard says Sports Basement rents crash pads for $30 a day. It also suggests downloading Mountain Project maps before you lose signal. Stay on the trails to limit erosion, and brush off any chalk marks you leave. New to climbing? The Standard suggests an intro bouldering class at a gym first. One option is the new California Climbing Collective in SoMa.

Getting there

The park is on Highway 35 (Skyline Boulevard), about 2.5 miles southeast of Highway 9. The Standard puts the drive from San Francisco at about an hour and 20 minutes. Free roadside parking fills up on weekends, but the official lot takes cards.