I live in SoCal and could write a book about diving here. I'll try to just hit the high points.
The diversity includes shore diving, wreck diving, oil rig diving, offshore islands, kelp forests, and aquarium diving. Between San Diego and Santa Barbara there are at least 100 shore diving sites offering different topography, marine plants, and marine animals. Most are easily accessible and the local dive shops can give directions, conditions, and tips on diving individual sites. In the San Diego area, about 2 miles offshore from Mission Beach, is Wreck Alley. Several ships have been intentionally sunk in depths well within sport diving limits. The best of these is the Yukon, a 350+ foot Canadian naval destroyer.
Farther north, offshore from Long Beach, there are 3 oil rigs that allow diving with prior consent. It's easiest to dive these on an arranged trip aboard a charter boat. It's a live drop off and pick up, since boats are not allowed to tie up on the rigs. You can expect to see large schools of bait fish, invertebrates like sea stars and strawberry anemones, sea lions, and a lot of other marine life. Whales are sometimes seen in this area. At any given time there are around 20 charter boats operating in southern California. They mostly take divers to the offshore Channel Islands.
In the south these are comprised of Catalina, San Clemente, Santa Barbara, and San Nicolas. The northern islands are Anacapa, Santa Cruz, Santa Rosa, and San Miguel. All of these usually offer great viability, and excellent opportunities for photographers and hunter/gatherers. One example of marine life found around the islands is the Giant Black Sea Bass which can weigh hundreds of pounds. They are making a wonderful comeback after having been hunted to near extinction. They have been protected for many years now and scuba divers are spotting them more frequently.
One of the highlights of diving SoCal is the kelp forests along the coast and around the islands. It's somewhat surreal diving amongst the fronds reaching from the bottom to the surface. Giant kelp is one of the fastest growing organisms on earth, up to 2 feet a day. The forests provide an excellent refuge for fish and invertebrates.
Another novel dive is at the Aquarium of the Pacific in Long Beach. For a fee, you can scuba dive in their largest tank surrounded by a myriad of sea creatures. It's a fun and thrilling experience. I have been a hunter/gatherer for many years and opportunities for game are plentiful: lobsters, crabs, scallops, mussels, clams, urchins, and many different types of edible fish. Abalone in Southern California have been under a moratorium for many years to allow rejuvenation of the species following a number of factors which severely depleted the population. The marine animals run the gamut from Blue and Grey whales to macro subjects like nudibranchs and seahorses.
The topside attractions are nearly endless: gorgeous beaches, world-famous zoos, theme parks, concert venues, museums, movie studios, some of the country's best restaurants, over a dozen professional sports teams, theater, symphony, etc.
Bottom line: Southern California is a diving vacation destination that rivals all others. This should really be considered a bucket list place that everyone should visit more than once.
