Is there first-come camp sit

Unfortunately NO, you reserve your camp site through Cruise america.com or Google reservations San Clemente State Park.

Yes Patrick's answer is correct but ranger did mentioned that they have no involvement in reservations online only. That said he said, he'd witnessed some found reservations quickly as there's always a cancelation. Again, on-line access for all reservations. It's well worth the effort though, feels like your own private beach as it's not overly crowded and only people stays there gets the beach all to themselves. Have a blast 😊