The elephant seal rookery is a beach that the seals return to each mating season, which occurs over the winter months. I'm a bit early for the season, so there's somewhat fewer than the usual 15,000 seals on the beach. It is also a tourist magnet, and for good reason. Although visitors are discouraged and largely unable to get on the beach, it is possible to do so but everyone respects the fences and stays on the observation platforms that line the beach.
While I appreciate the respectful attitude visitors have, it does create a bit of a problem for photographers. First, a long lens (300mm or better) is a good idea. That means "tripod," and I found the foot traffic and general jostling for space among the group a bit of a challenge. I tried at first to do a handheld-shot propped on the rail, but people kept bumping into the rail, spoiling the stability. I couldn't fault them--it's a fascinating place, but the earlier in the day you arrive, the better off you probably are, and a tripod or at least monopod is necessary.
In any case, Piedras Blancas is a must-see. It's a treat to see the seals up close and personal, sleeping, snoring, barking, roaring, and watching us with a wary eye.