I know that technically these Islands are just over the U.S. border in Mexico, but they are commonly accessed from San Diego. I went out on a "Dive Connections" charter out of Mission Bay on Nov. 17, 2007. It was about a 1-hour trip to the Northern-most island and a site called "Lobster Shack" after some lobster-fisherman's shacks that used to be on the steep shore. They didn't mind me diving by myself so I jumped in to 40 to 50-foot visibility and a rocky-reef/boulder bottom that met sand at about 60 feet deep. In the shallows near shore there were swarms of California sea lions  mobbing the divers. Deeper down, there were clusters of fan-like gorgonian corals and a few moray eels peeking out of their dens. At all depths there was a variety of fish darting around, including garibaldi. Out in the sand there was the remains of a cabin-cruiser that hit the island a few years ago. It seemed that just the top of the bridge area was left sitting on top of the sand. I don't know where the rest of the hull went. Strawberry anemones were growing on the wreckage and sealions were wrestling in the sand nearby. Overall, the trip was definitely worth it.