The La Jolla Underwater Park is a great way to experience the world in the Pacific Ocean. There are artificial reefs, two canyons and a kelp forest. There are many places around the park to rent scuba and snorkeling gear, kayaks and wetsuits.
The park lies underwater between Torrey Pines State Park and La Jolla Shores. I've swam here and kayaked. Even from the kayak the water is clear enough to see the ocean life, such as the garibaldi- the bright orange state fish of California. I've experienced run ins with seals, dolphins and stingrays. The most breathtaking experience was when I almost swam right on top of a leopard shark, these large, docile fish are incredible to see- especially when you're in the water with them!
Tip: The area is marked well by buoys and is probably the best place along the southern CA coastline to go snorkeling because the water is more calm here than other parts of the coastline. If you go, be watchful of other swimmers, kayakers, snorkelers and divers as this can be a popular place.