Sea Caves
These caves have formed along the California coast and on our offshore islands. Hundreds exist and some are surprisingly large.
Geology
Sea Caves can form in any kind of hard rock that lies along the California coast line. With sea caves the ocean finds a crack or fracture and the ever present surf, particularly during storms, slowly eats away at the weakness, eventually forming a tunnel or room inside the cliff face. Sea caves can occur anywhere with a rocky coast line in the state. They are most common in the Channel Islands in southern California where there are hundreds, including the largest, Painted Cave, which is 1,200 feet long with an entrance 130 feet tall. Other larger sea caves are found in San Luis Obispo, Santa Cruz and Mendocino counties.
Sea caves are important for sea life ranging from small invertebrates, to kelp to seals and sea lions. They offer a protected location away from storms and surges as well as predators.
The caves are often linear since they follow cracks and fractures in the rock. They may extend deep underwater, offering more refuge for wildlife. Frequently, they are largest at the entrance and slowly get smaller the deeper one goes. Sometimes another crack or fracture intersects the cave and another passage forms along it, adding to the complexity.
How can I see a California sea cave?
In La Jolla, check out Sunny Jim’s sea cave. It is a unique California experience and accessed via a dug tunnel and a long flight of stairs. Leo Carrillo State Park in Malibu is also known for its sea caves.
Sea Cave Safety
Active sea caves can be dangerous for swimmers or boaters. Surf and waves can easily move people and boats into the walls and ceiling of these caves causing injury and even death. It is usually best to stay out of sea caves in the surf during your coastal adventures and leave it to the seals.