For 900 miles, ocean swimmer Catherine Breed reckoned with El Niño

Mill Valley resident Catherine Breed has finished her roughly 900-mile swim of California’s entire coast. To achieve this unprecedented feat, the 33-year-old swam through open water for about five to eight hours per day – and faced an unexpected foe.

Since starting at the Oregon border in July, Breed experienced this year’s historic El Niño changing the Pacific Ocean in real time. She shared what she witnessed and how El Niño complicated her team’s journey with SFGATE on Saturday afternoon, two days before her ceremonial finish.

In this conversation, Breed voiced concern about a surprising current, which seemingly flowed north as she attempted to travel south. Josh Willis, a senior research scientist for NASA’s Jet Propulsion Laboratory, told SFGATE that El Niño has not changed the far offshore California Current, which flows north to south, but he had another theory. “Near shore, there is a small coastal jet that also goes from north to south most summers, driven really by the upwelling and the winds near shore,” Willis wrote via email. “But during an El Niño year, those upwelling winds tend to reverse and the coastal jet can stop or reverse as well. This is probably what Catherine was experiencing.”

This interview was edited for length and clarity.

SFGATE: What happened on your swim today?

I swam from Point Loma to Mission Bay, which was about 8 miles. When we were coming back into the San Diego harbor, there was so much trash – like more than I’ve seen the entire trip. There were a lot of plastic bags.

Catherine Breed comes ashore at Coronado Beach in Coronado, Calif., on Oct. 19, 2026. (Adrian Childress/For SFGATE)

Catherine’s sister and nephew welcome her on Coronado Beach. (Adrian Childress/For SFGATE)

SFGATE: What’s on your mind for the last leg to the California-Mexico border?

The Tijuana River is a global, national and California crisis. Essentially, raw sewage comes out of the river and spills into the ocean. The pollution zone is about 1.5 miles offshore, so I’ll be finishing around 3 miles offshore, crossing the border at sea. That’s why no one’s gonna see me finish. The strategy for avoiding the pollution crisis is to 1) avoid, and 2) I’ve started taking prophylactic antibiotics at the guidance of my medical team. Thank goodness it’s at the end.

SFGATE: How are you feeling so close to the end?

Physically and emotionally, I feel great. We had a really fun day in the ocean today. My body’s holding up great. I think, mentally, I am ready to be done. I’m ready to be home. I’m a little overwhelmed at some of the attention that’s going to come from the finish.

SFGATE: What should Californians know about your observations underwater?

Breed: I want to underscore how challenging this was during the super El Niño. I picked this year out in 2023, and I had no crystal ball saying it would be a super El Niño. It really forced us to work with Mother Nature every single day. It proved extremely challenging for the swim … My message to people would be to get involved in local ocean conservation to understand what’s happening in your backyard. I do believe that this year is an alarm for us.

Fans and relatives congratulate Breed on the beach. (Adrian Childress/For SFGATE)

Catherine Breed speaks to fans, family and media after she completed her 900-mile swim of the California coast, on Coronado Beach in Coronado, Calif., on Monday, Oct. 19, 2026. (Adrian Childress/For SFGATE)

SFGATE: What signs of El Niño did you notice?

We’ve definitely been feeling the warmer water. We started noticing that all the way up in San Francisco, where it was warmer than it typically has been in other years. The fact that there was so much activity, in the forms of hurricanes and tropical storms in the Pacific, was also very noticeable. We were in Hurricane Rachel, and we definitely got swell from the other storms. Having a lot of big swell from the west or the south made it difficult to anchor at times.

The other thing we’ve noticed is the shifting current. It seems to be going in the opposite direction than it typically does, but I need to do some research on that … The current plus the hurricanes and tropical storms meant that I had to reverse direction sometimes. Instead of all my sections swimming north to south, I did some segments where I swam south to north. That doubles our time in the ocean. It doubles transit time. It forces us to really think about our day in a very strategic way.

SFGATE: What kinds of marine life did you see?

We saw a lot of manta rays, which I thought was pretty unique. We saw them as far north as Malibu. They are a tropical species, so having them this far up north was interesting. We definitely saw tuna and marlin. We also saw many sea lions affected by domoic acid in Monterey.

And there were lots and lots and lots of whales – in the hundreds. I had a whale swim underneath me in Humboldt County, and then I had dolphins swim right near me in Mendocino. Bottlenose dolphins in Santa Barbara played with me for like 10 minutes, which was so amazing.

Up around Morro Bay on the Central Coast, a baby humpback and a mother humpback swam within like 15 to 20 feet of me, and that was probably the coolest experience of my life.

We were seeing like 10 to 20 whales per day. And then, all of a sudden in the Santa Barbara area, we didn’t see any whales anymore. That could also be because it was warm.

Catherine Breed stands with her sister and nephew Leo in the water at Coronado Beach. (Adrian Childress/For SFGATE)

They’re pretty uneventful. The crew is always looking out, and I’m swimming very close to the boat. If the crew sees a fin, they just tell me, “Cat, shark!” I hop out within about 5 seconds. If we see it again, we evaluate if we should get back in the water or just be done for the day. One day, we did make the call to be done. But most of the time, I resume my swim, and that’s it.

SFGATE: After this incredible accomplishment, what’s next for you?

I’m going to a wedding in Central America, so I’m gonna go enjoy a little vacation. And then I will really just focus on my next step in life professionally. I want to see how I can use this swim to share a story that inspires not only ocean conservation but also more people to go after big goals and push themselves.

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