Ötillö Swimrun Casco Bay 2026

The SwimRun Casco Bay is where the history of American SwimRun took its first big plunge—and you’re coming to write the next chapter on Great Diamond Island (Casco Bay, Maine) 🌊.

Expect sea crossings that wake you up, tides that change the vibe from one passage to the next, coastal-trail sections where you play with your footing, and pieces of history that pop up around the bend of a path 🪨.

You choose your adventure: the Casco Bay Sprint to discover without burning out, the Casco Bay Experience for a true “best-of” of the islands, or the Casco Bay World Series to taste the legendary version—the one that makes you say, “okay, that’s why I came” 🏁.

After the finish line, stick around: take a detour to Fort McKinley on Great Diamond Island, then hop on the ferry to go stroll through Portland (the Old Port and its wharves), or head out to the Portland Head Light in Cape Elizabeth for the coastline’s great classic.

If you’re coming as a duo or with family, plan an end-of-day on Peaks Island (bike rentals, little beaches), or simply a sunset walk along the shore of Great Diamond Island: salt on your skin, a smile on your face, and the feeling you’ve just had your best day.