California beach camping is very popular, so most campgrounds do get crowded during the peak summer months. But there are some places that are less crowded, or where the campsites are roomy enough that the crowds aren't a big issue.
One of the best spots for camping along the Central Coast is the Kirk Creek campground
in Big Sur. It's located on a bluff overlooking the beach, and the views are spectacular. The campsites are spacious enough that you won't feel overly crowded even when the campground is full. There's a trail leading down to the beach, and decent amenities.
You'll have the best luck escaping the crowds at Montana de Oro State Park
, south of Morro Bay. It's just a bit off the beaten path, and the campground is primitive: pit toilets, no hookups, no showers. But there are picnic tables, fire pits, and drinking water. The campground is located on a coastal terrace above Schooner's Cove, a scenic pebbly beach, popular with visitors. The park features lots of trails, gorgeous views, and abundant wildlife.
If you've got your heart set on camping in Santa Barbara, or close to it, your options are limited. Both Refugio State Beach
and El Capitan State Beach
have good facilities and lovely beaches, but they both have the drawback that Highway 1 and a railroad track abut the park. They're also very popular, so crowding can be an issue.
About 60 miles north of Santa Barbara is Jalama Beach County Park
, which doesn't have the noise problems of the other two beaches. However, it's very popular, and can get crowded.
Hope this helps.