Exploring the Underwater Wonders of San Diego
- Marissa Charters - As Captain Lora
- May 18
- 4 min read
San Diego might be known for its beaches and burritos, but below the surface lies a whole other world—one filled with kelp forests, shipwrecks, and wild encounters. But here’s the thing: San Diego diving isn’t tropical, and it's best to know what to expect in cold water diving. Even though cold water diving can be challenging, it is also what makes it awesome.
At Marissa Charters, we specialize in small-group boat dives to San Diego’s best offshore sites, from Wreck Alley to Point Loma and beyond. If you’re planning a dive trip here, this guide will help set real expectations—minus the travel brochure fluff.
The Underwater Wonders of San Diego
San Diego boasts several wrecks in wreck alley, as well as beautiful kelp forests. The Kelp is Majestic! Really and truly an experience. San Diego's Kelp forests suffered a massive blow during the last 2 El Niño weather patterns. California giant kelp (Macrocystis Pyrifera) thrives in cold waters, this brown algae prefers 40ºF to 68ºF waters. During the El Niño years, the local water temperatures increased so much, we experienced a massive kelp die off. We used to have kelp so thick you could not drive the boat through it all the way out to 100' depth. Now we have a few patches of kelp that mostly remain all year.
Kelp Making a comeback
In 2024, the water never really "warmed up" we experienced a high of about 56-58ºF at depth. The kelp initially grew in thick patches but quickly diseased and died off again. However, we have more hope, this year the kelp looks really healthy! I am hopeful that by summer time we will have some thick patches we can take you to. Additionally, we have had other varieties of kelp take its place. We have several more bull kelp (Nereocystis leutkeana) stalks and low lying algae that were not as common here. Needless to say, the rocky reefs of point loma and the sandy /rocky shores of La Jolla are still beautiful dive sites.
Point Loma is one of my favorite areas, known for its dramatic underwater bathymetry. This area features deep canyons and unique rock formations that provide shelter for numerous marine species. The sealife here is so diverse, numerous nudibranchs in every field of vision, lingcod, sheepshead, hornsharks and seven gill sharks!
What to Expect Underwater
Cold Water, Even in Summer: San Diego is a temperate water destination. Expect temps from the high 40s (winter/spring) to low-to-mid 60s (fall). Most of our divers wear a 7mm wetsuit with hood, gloves, and boots—some go full drysuit. Either way, proper exposure protection is a must.
Visibility Variability: Traditionally we get epic autumn days with visibilty up to 100', however this year we have had consistent winter visibity , of 40'+! usually in the winter we either have awesome (40'+ or terrible visibility). We are looking forward to an epic summer and fall! Typically we expect an average of 15–20 feet, annnnda on those special days closer to 5'. I find being mentally prepared for 5' visiblity really allows divers to have better dives. If you are expecting 5' and get 30' you are going to be stoked! if you are expecting 100' tropical visibility and get 5' it is much harder to adjust your mindset. No matter the visibitly the ocean always shows us a good time:)
Why Boat Diving Beats Shore Diving in San Diego
While shore diving at La Jolla is popular, it’s not what we do. Our charters take you to sites you can’t reach without a boat—and trust us, they’re worth it:
Wreck Alley: Dive iconic artificial reefs like the HMCS Yukon, Ruby E, and more. Expect depths from 75–100 ft, overhead environments, and lots of marine growth. Great for Advanced divers and beyond.
Point Loma Kelp Forests: Towering kelp, sea lions, and hidden canyons. Sites range from 45–90 ft and are some of the most dramatic kelp environments in California.
Deep Reefs & Technical Sites: We regularly run technical charters to places like Murray Head, Hogan, and even military plane wrecks. Certified and ready for a challenge? You’re in the right place.
What You Might See
We get asked all the time what kind of wildlife to expect. Here’s a quick list based on our most frequent sightings:
Giant black sea bass (summer/fall)
California sea lions (playful and curious)
Nudibranchs galore (anytime, alll the time)
Spiny lobsters (especially at night)
Garibaldi, sheephead, and schools of baitfish
On lucky days: torpedo rays, horn sharks, seven-gills
Final Thoughts
While San Diego diving isn’t always easy—but it’s always worth it. If you're ready to experience the real underwater California, a boat dive with Marissa Charters is the best way to do it. We won’t sugarcoat the conditions, but we will give you safe, fun, and memorable dives every time.
Want to book your next dive? Check our calendar and come explore with us.
Comments