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5 Most Epic Triathlon Swim Courses

Swirling currents, ice-cream headaches, and even salt-plus-freshwater combos—we asked the pros to rank the toughest swims in the triathlon world.

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Out of the three legs of a triathlon, the swim course can be the most drastically altered by unforeseen weather conditions. Take a glassy body of water and add in some extreme wind or strong currents, and suddenly you find yourself swimming in a washing machine. Choppy waves, chilly temps, and foggy conditions can all turn a mellow swim into an adventure. We asked a handful of pros to name the most difficult swim courses on the race circuit and these five rose to the top.


Related: Triathlon’s 7 Most Brutal Bike Courses

Related: The 5 Toughest Run Courses In Triathlon

Photo: Carlos Avila Gonzalez/San Francisco Chronicle

Escape From Alcatraz

From 1934–1963, San Francisco’s Alcatraz Island housed more than 1500 prisoners in its federal penitentiary, including Al Capone and George “Machine Gun” Kelly. Frank Lee Morris famously escaped from Alcatraz and was never found—and the infamy of the rough San Francisco Bay waters live on in this challenging 1.5-mile swim course.

The swim from Alcatraz Island to San Francisco’s Aquatic Park starts in an unconventional way: You jump straight off a ferry into cold, rough, foggy waters that feel like a river moving in unusual directions. Some of the sport’s strongest swimmers—including Andy Potts, Eric Lagerstrom, and Lauren Brandon—cited this course as the most difficult. “The Alcatraz swim is pretty epic! If you get a slower day, it can make the swim really exciting too,” said Potts, who has won the race six times. “You’ve got the anticipation of the jump from the Hornblower, the landmarks to sight off of—although I don’t see many—and the cold temps. It is awesome.”

Photo: Rocky Arroyo

Ironman World Championship

There’s a reason only the best in the world can tackle this ocean swim every October. It may look like swimming in paradise, but the 2.4-mile Kona course is no joke. “The salt, the waves, the warmth, and the unknown in this ocean swim course dominate me every time!” said Meredith Kessler, who has raced at the big show on the Big Island seven times. “Not only is it nerve-racking to swim 1.2 miles out (and then back!) to what seems like the middle of the ocean, but the constant fluctuation and bumpiness of salt water blasting you in the face, for me, makes it one of the hardest swim courses on the circuit.”

Sarah Piampiano, who has finished in the top ten in Kona twice, echoed those thoughts. “The water there is so salty that it is very dehydrating,” said Piampiano. “I find the constantly-changing currents along the course very hard to read and manage, and the swells can be tough.” Because the swim tires you out in a way that other courses might not, she said, the first part of the bike becomes even more critical to manage when you’re taking in calories. “You can’t eat and drink too soon because the ocean swim can cause sea sickness, but you need to eat and drink soon enough that you get in energy to offset the energy used on the swim.”

Laguna Phuket Triathlon

Held on Thailand’s biggest island, the Laguna Phuket Triathlon draws international competitors to race the 1.8-kilometer swim, 50-kilometer bike, and 12-kilometer run course through the countryside, local villages, and stunning beaches. The swim here poses an interesting challenge: You swim in both salt and fresh water—starting in the Andaman Sea and finishing in a fresh-water lagoon.

“You do a loop on the ocean and then have to run across the beach and swim through a lake to transition,” said Tim O’Donnell, who won the race in 2010. “It’s so much fun, but when you get out of buoyant salt water and hit the fresh water, it feels like you are swimming through quicksand!”

Photo: Gregory Shamus/Getty Images

Ironman Florida

When the waters are calm during this November race in Panama City Beach, the swim can be a two-lap pleasure cruise around the Gulf of Mexico. But, as Matt Hanson (who took second in IMFL in 2020), points out, “The toughest courses on the circuit are such a weather-dependent thing. Ironman Florida can be an easy swim, but there have also been years where people couldn’t get through the surf starting the second lap because the wind kicked up.” Even in the course description, Ironman mentions that “strong currents, riptides, and occasional marine life are possible.”

Photo: Janos M Schmidt/ ITU Media

ITU Long Course Worlds in Oklahoma City

Although this race moves venues, the difficulty of the 2016 swim course in Oklahoma City’s Lake Hefner was so epic that it stuck with Skye Moench years later. “The water was so shallow, murky and choppy, and it was multi-loop so there were a lot of people congested on course,” said Moench, who took eighth place that year. “I remember standing up in the middle of the swim with a few other female pros and we all looked at each other in complete shock—that was a hilarious moment. It took forever to complete that swim, and it seriously felt like it would never end in those conditions.” Although the ITU race has moved on, the half-distance Redman Triathlon still takes place in Lake Hefner if you’re up for a challenge (note: cancelled for 2021).