San Diego-La Jolla Underwater Park, Marine conservation park in La Jolla, United States

The San Diego-La Jolla Underwater Park is a marine reserve off La Jolla in San Diego, made up of the San Diego-Scripps Coastal Marine Conservation Area and the Matlahuayl State Marine Reserve. It covers about 6,000 acres of ocean bottom and tidelands, including La Jolla Cove, with four habitats: rocky reef, kelp bed, sand flats and submarine canyon. Above the water, the coast is a 75-million-year-old sandstone cliff cut by seven sea caves and an archway.

In 1929 California set aside a marine life refuge near the Scripps Institution of Oceanography. In 1970 the City of San Diego incorporated the San Diego-La Jolla Underwater Park, over two miles offshore, and created the 514-acre Look, Don't Touch Ecological Reserve. The San Diego Council of Divers, led by Harold F. Riley with support from Conrad F. Limbaugh, spearheaded the project, and the Bottom Scratchers Dive Club helped. In 1981 the reserve was extended to include La Jolla Cove.

Marine biologists conduct research in the park's waters, studying the behavior of leopard sharks, sea turtles, and numerous fish species in their natural habitat.

You can enter the park through La Jolla Shores Beach and explore it by swimming, snorkeling, or paddling a kayak along the shoreline. Local rental shops near the beach provide all the gear you might need if you do not have your own.

The seven La Jolla sea caves, once called the Mammoth Caves, were carved by the sea into a 75-million-year-old sandstone cliff east of La Jolla Cove. At low tide they can be reached from the water, but only Sunny Jim's Sea Cave is entered from land, through a tunnel dug in the early 1900s from the Cave Store on Cave Street.