If you want to get a good space with good shade you're going to want to get a reservation. For weekends you might want a reservation cuz they fill up faster. During the week you can usually just show up and there's 20 open camping sites. I like 31 & 15 best!
If you want to pick the exact spot you want. You have to reserve. Otherwise first come first serve. You can reserve here https://www.sbcountyparks.com
Is better to reserve it to get a good spot.
Just go early.
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