So, seriously, where is a good place to park when visiting Mission Beach, Pacific Beach, and/or La Jolla? Nothing is more frustrating than being able to see the beach from your car window but not being able to get out b/c you can find a parking spot anywhere! Know what I'm sayin'?
You simply have to commit to getting there early. I know it's a drag, but if you want to enjoy your day, you have to get an early start.
Mission Beach — the parking lot near Belmont Park. Make sure you have a club on your wheel, and nothing tempting in the car. (Put a Bible on the passenger seat!) Occasional gang activity at South Mission Beach.
Pacific Beach — well, it depends where. You've got Tourmaline which is north P.B. Lots of surfers, but you have neighborhood parking.
La Jolla — the only place I take my family. And we get there NO LATER than 11 a.m. However — since we live in San Diego, we're only body surfing for a couple of hours. Parking in the neighborhood north of the La Jolla Shores parking lot is good for 2 hours, and generally you WILL find a curbside location, though you might have to walk 3 blocks.
If you want to stay longer, then you MUST get to the main parking lot by 9 a.m.
AS FOR THE OTHER BEACHES:
Keep in mind that anywhere south of La Jolla will be polluted from the Tijuana discharge which flows north. That includes the easily accessible beaches on the SIlver Strand, even Coronado.
Mission Bay is terrible. It's an unknown secret that it's polluted 9 months out of the year, but the Tourist Bureau / Chamber of Commerce keeps it quiet.
Ocean Beach has parking in the neighborhood within a few blocks. You should shoot down Newport Avenue to the parking lot on the end (left side, near the pier). You might get lucky, and if not, well, you might have spotted curbside parking near the stores which has no time limit.
If you live in San Diego, you will have a MUCH EASIER time finding beach parking once school begins in September.