Locals... Beaches near Alamo, CA?

So my friend and i live around the Alamo, Walnut Creek, Concord, Danville area in the Bay area in California and once it gets warmer we really want to go to the beach! But we're both super busy so we can't fly anywhere or drive somewhere that takes like 10 hours to get to because it'd prob be for the weekend or somethin. Suggestions? Is santa cruz good? And try to be specific, thanks :)