If you want a beach away from the crowds--even in the summertime--you should consider Dockweiler State Beach and/or the beaches of the adjacent tiny village of Playa del Rey. Dockweiler Beach is at the end of the Los Angeles International Airport runways, and there are plane take-offs every few minutes overhead. Okay--so that's the downside. But, the up side is that many people leave this beach alone. I say, WHY? The chance of a plane crashing onto you is much less than the chance of your getting into an accident in your car on the way to the beach! This fine beach has clean, white sand---and it's nice and wide, so it never fills up, even on the busiest summer afternoons. There's plenty of free on-street parking, and there are also large parking lots.
Other than restrooms, there aren't many facilities, but that too keeps the crowds away. The wide stretches of sand are punctuated by green oases of grass and tall stands of palm trees. The beachside bike path splits into two separate lanes here, so there's plenty of room for your sports activities and not a lot of onlookers either, if you're self-conscious about your performance! The little residential village of Playa del Rey, adjacent to the north end of Dockweiler Beach, also has fine sand beaches that are generally only used by the town's residents, and the planes don't fly directly overhead there. The town has several restaurants in it's little business district. (There's no food available at the beach there.) You'll also find a large, grassy park with play equipment for the kids not far from the beach in Playa del Rey.