Help Sean Bannon Achieve the Arch to Arc Triathlon

Hi, I’m Sean Bannon—an endurance athlete, cancer research coordinator at Massachusetts General Hospital, and someone who believes that movement is one of the most powerful forms of medicine we have.

In June 2024, I became the 1,910th person to solo swim the English Channel. This year, I’m continuing that momentum with two more of the world’s most demanding swims:

The Catalina Channel Swim – Over 20 miles through cold, dark, shark-inhabited waters off the California coast

20 Bridges Manhattan – A 28.5-mile swim around New York City, under all 20 of its bridges

Together with the English Channel, these swims make up the Triple Crown of Open Water Swimming. If successful, I’ll join a small group of athletes who have completed all three—each a feat of endurance, logistics, and grit.

But I’m not stopping there. In 2026, I’ll attempt the Arch to Arc Triathlon, widely regarded as the hardest triathlon in the world. It starts with an 87-mile run from London to the coast, followed by a solo swim across the English Channel, and ends with a 180-mile bike ride to Paris. Fewer than 60 people have ever completed it—and if successful, I would become the youngest person to do so.

These events are not just about testing limits. They are about raising awareness for the power of physical activity—to prevent disease, promote mental health, and transform lives. As someone who works with cancer patients every day, I’ve seen how movement can become a form of healing and empowerment.

But these challenges come with real risk and significant cost. People have died attempting the Channel swim—which is why safety is everything. Each event requires permits, escort boats, experienced crew, medical oversight, and travel—adding up to nearly $15,000 in total costs.

Your support helps keep me safe, gets me to the start line, and allows me to use these efforts as a platform to advocate for movement, health, and resilience.

Thank you for believing in the mission—and for helping me go the distance.