I first visited the Piedras Blancas seal rookery in 2010 on my first visit to the Central Coast area. In December the seals are cheek-by-jowl, jostling for space and trying to catch the weak winter sun. Lest you think that this is a quiet, sanguine little beach, the seals are constantly snorting, barking, growling and making farting noises that will leave the 8 year-old in you snickering. Graceful only in the ocean, they shuffle, roll and collapse into scattered heaps of blubber. Their only captivating features are their eyes.
The main Piedras Blancas seal observation area is often busy, filled by tourists spilling out of buses and jostling each other for good spots to get photos of the seals. However, the seals are often too far away for really good shots unless you have a long telephoto. Even then, setting up a tripod will get you scowls and people are likely to trip over it, ruining your shot. There's a wooden fence keeping visitors from encroaching on the seals' territory, and for good reason, given some folks' judgment. Bottom line, it's not easy to get a good shot here. But, there's a solution.
Head 1.3 miles south of the main observation area and you'll find a parking lot at the "Vista Point." (Look for the blue sign.) Park at the southernmost end of the lot and then take the path at the end of the lot about 100 yards further. You'll find yourself on the edge of a bank 10' or less from the seals, where you can get as many shots as you want. The two times I've visited this spot I've had it to myself.
The seals are either curious, napping or preoccupied with their battles for territory. There is no fence, but of course you absolutely should not climb down the bank. There's really no reason to--you can get all the shots you want with little effort. Respect the seals and leave them to their little corner of the coast.