Lake Titicaca Double Zemaitis Route (Copacabana to Isla del Sol and back) - March 18, 2026

In 4th grade, I won my class geography bee by correctly answering that Lake Titicaca is the highest elevation lake in South America. This sparked a lifelong dream to merely visit this incredible lake. At 12,500 ft, Lake Titicaca is the highest navigable lake in this world and has significant cultural meaning as the homeland of the Incas. 8 year old Corey could never have imagined swimming in it, let alone swimming her longest swim ever in the magical Lake Titicaca.

Yesterday was a dream come true, but not without challenges. The first 15km were some of the hardest swimming conditions I’ve ever faced. With unpredictable, rather big chop, and water temps around 60.4F, this fresh water swimmer was not having a fantastic time. For me, altitude feels like heaviness in the arms—and I certainly felt that for the first half. I was fully ready to quit at the turn, recognizing it would still have been an amazing accomplishment to swim one way (only like 7 or 8 people have done so). Physically I felt fine, but mentally I was not in a fantastic place.

After a conversation with Ryan Willis at the turn, he convinced me that I needed to at least start swimming back and see how I felt. I don’t know if it was some magic from the temple del sol (a 1400s Incan temple located at the turn/one-way finish), the pep talk from Ryan, or some good snacks, but I felt better after the turn. Conditions died down and I was swimming faster than I had for the first 4.5 hours. And the sluggishness was gone!

I told myself I just had to make it back to the tree. And then I just had to make it 3 feeds beyond the tree. And then Sarah told me I only had 7km left. “I can do 7km.” I told myself. And then the sun came out, a blessing. And then I saw the white hotel—my landing spot. My exit was ugly. A combination of extremely rocky and debris-covered beaches make the act of standing after 9.5 hours challenging. But wobbling onto shore, I saw the wonderful faces of new and old friends. I was just grateful I stuck it out.

Big thanks to my crew Sarah Thomas, Ryan Willis, and pilot Max. Thanks to Joe and John Zemaitis for organizing this adventure and pioneering this route.

A huge congrats to everyone who swam this week. This swim is incredibly challenging. From duck itch, to altitude, to cold water, to unpredictable chop, we all had to endure a lot (even swimming one way). It’s a massive accomplishment to swim in this lake at all. I already mentioned my crew, but I am ever so grateful for the mentorship and care both Sarah and Ryan have provided me this trip. They have kept me hydrated and safe. They are special people. And I’m glad to have them in my life.

Unofficially the first double crossing (of this route) of Lake Titicaca. ~31km in 9.5 hours. Officially my longest swim ever.

• Lap 1: 4:32:02 (fastest one way, Copacabana to Isla del Sol)
• Turn time: 7:07
• Lap 2: 4:51:29
• Cumulative Time: 9:30:39, First and fastest double