Navigate marine mysteries in the La Jolla Underwater Park

Last Updated on September 18, 2025

Read on as we unmask the spectacles under the sea.

No guide to La Jolla – or San Diego – would be complete without exploration of La Jolla Underwater Park. Officially called the San Diego-La Jolla Underwater Park Ecological Reserve, its 6,000-acre area of ocean floor is larger than La Jolla’s area above water, an actual hidden gem of tourism and beauty under the waves.

This marine sanctuary is a paradise for locals and tourists alike, offering a fascinating glimpse into the diverse and vibrant world beneath the ocean’s surface, and yes, you can enjoy parts of it from above the water, too.

Take a deep dive into our guide to the La Jolla Underwater Park and its riches, and prepare yourself for a grand ocean adventure.

Bountiful biodiversity

The San Diego-La Jolla Underwater Park Ecological Reserve extends from La Jolla Cove northeast to the middle of La Jolla Shores Beach and includes four main areas and a wealth of creatures:

Kelp Forests

These towering underwater forests provide shelter, food, and breeding grounds for a wide variety of marine species. Giant kelp, with its long fronds and lush canopy, creates a mesmerizing underwater forest where sunlight filters through. The kelp beds are truly a bustling underwater metropolis, where every nook and cranny hides creatures dependent on the kelp to live. Although the kelp forests in La Jolla have been declining over the years, they remain a must-see within the park.

Submarine canyons

A black and white contour map depicting the underwater topography of Scripps and La Jolla Canyons. The map features contour lines representing different depths, with closely spaced lines indicating steeper areas of the submarine canyons. Key locations such as "Boomer Beach," "The Cove," and "Scripps Institution of Oceanography" are marked, along with the positions of the underwater formations. The contour intervals are marked in feet, and the map provides a detailed view of the complex underwater terrain of the La Jolla Underwater Park area

Shepard and Buffington’s classic map via PV LAB- Woods Hole Oceanographic Institution.

The La Jolla Canyon and Scripps Canyon make up the two submarine canyons off La Jolla’s coast. The narrow valley of Scripps Canyon, located closer to the Scripps Institution of Oceanography, connects with the deeper La Jolla Canyon, 1.3 miles out, with a meeting point depth of over 600 feet.

Above water, the canyons are responsible for large waves adored by surfers. Below, the canyons are a treasure trove for researchers, scientists and divers eager to engage with the abundance of marine life in the area.

Reefs

These underwater formations are teeming with life, with crevices and caves providing refuge for an array of marine creatures, much as the kelp forests do.

The La Jolla Underwater Park also has two artificial reefs, man-made structures strategically placed along the coastline to provide additional habitat for marine life, promoting the biodiversity La Jolla is known for.

The seven sea caves

Visitors to La Jolla Underwater Park should not miss the opportunity to see the incredible and regal sea caves towering over La Jolla Cove. The seven caves are mostly accessible only by sea, but are worth the effort.

The caves’ unique formations and openings, carved into the rocky cliffs, provide a mystical experience as visitors go through narrow passages and marvel at the natural geology.

Sunny Jim’s is the only cave accessible from land and can be accessed from inside The Cave Store, via 145 historic stairs.

Within the La Jolla Underwater Park’s vast variety of formations are the hundreds of aforementioned species, from the bright orange Garibaldi fish – the state fish and inspiration for Dr. Seuss (yep, he lived here!) – to the cormorants and pelicans and the breathtaking whale or dolphin. Also notable:

Leopard sharks

Great numbers of leopard sharks visit the La Jolla Underwater Park annually, swimming in the warm shallow waters close to La Jolla Shores.

These gentle, harmless creatures never fail to thrill, as swimming alongside these majestic fish is a magical experience that few other destinations can offer.

Sea lions

While exploring the La Jolla Underwater Park, your chances of seeing a sea lion playfully swimming around you are high, and it’s certain you’ll see more than a few walking above or along The Cove.

These pinnipeds are arguably the loudest citizens of The Cove, calling to each other as they “walk” on their flippers on land or frolic in the ocean.

As approachable as they seem, please remember they are large and wild: stay 50 feet back.

(Looking for seals? They’re in La Jolla too, a short walk south at The Children’s Pool.)

Craving more creatures? Other sharks? Sea turtles? A rarely-seen species? The La Jolla Underwater Park has them, and we can’t get enough.

Defending the flora and fauna

Keeping the La Jolla Underwater Park a flourishing ecosystem for marine life is its inclusion in the Matlahuayl State Marine Reserve (SMR), one of three state-protected Marine Protected Areas in La Jolla where ocean activities like fishing and boating are restricted.

The creation of the La Jolla Underwater Park as an ecological reserve is credited to the Bottom Scratchers, a group of free divers founded in 1933 who fought for fishing limits on the dwindling numbers of ocean species.

The Matlahuayl SMR, named for the Kumeyaay word for “place of many caves,” was established as the San Diego-La Jolla Underwater Park Ecological Reserve in 1970.

Each area within the La Jolla Underwater Park is regulated in order to protect the native natural marine and geological resources and help all underwater sea life, both plant and animal, thrive.

Ready to explore? The La Jolla Underwater Park offers a range of activities for beginner or experienced outdoor enthusiasts to experience its natural marine wonders. Discover the best ways to explore here.