The 2016 SwimRun USA Casco Bay Islands

The first island to island style SwimRun race hit US-soil on Sunday in Maineís Casco Bay Islands off the seaport city of Portland. 121 two-person teams started out over the 4-miles of swimming and 10-miles of running over seven different islands and all but four teams completed the course.

Dan Kimball and Marcus Barton are a very experienced and accomplished team, and they were in a tight race for the menís podium throughout the day.

Earlier that day, following a half hour delay due to heavy fog the race got underway on Chebeague Island with a 1.8-mile run.

Matthew Hurley and John Stevens from Portland, Maine, arrived on the rockiest section of the course at Vaill Island with sizeable lead on the other teams.

The second team to come ashore on Vaill Island was the mixed team of pro triathlete David Thompson and Bridget McCoy from Minnesota.

Teams pacing over the rugged terrain on Vaill Island.

The exits and entries of some of the swims required careful attention to footing.

A womenís team experiencing some of Casco Bayís natural habitat following the longest swim passage of the race.

Racers are welcomed to Peaks Island after a 1700-yd swim with an aid station and enthusiastic spectators.

On Peaks athletes, including married couple mixed team Bronwen and Gregory Dierksen, tackled the longest run of the day, a 3-mile run across the island.

Womenís team Sara McLarty and Misty Becerra used Casco Bay Swimrun as a final tune up for Otillo in three weeks.

Teams strung out on Seashore Avenue on the way to Torrington Point on Peaks Island.

Barton and Kimball taking on nutrition before the swim leg from Torrington Point to Cushing Island in the later stages of the race.

The winning menís team Hurley and Stevens at the finish line.

The winning mixed team was Thompson and McCoy with their lobster buoy awards.

The winning womenís team Erin Hunter and Emily Finanger at the finish. The teammates also finished third overall in the field of 120-plus teams.

A steady stream of teams were equal parts elated and tired at the finish.

Twin sisters Anna and Grace Senko and Kristen Connors and Molly Lunn all smiles at the finish.

Michael Collins and Tim Vibrock came from Texas to compete.

Maryanne Dunfey and Katrina Zelenski were the last official finishers of the day.

Staff Sergeant Travis Mills was one of only five quadruple amputees from the Iraq and Afghanistan wars to survive after an IED explosion in 2012. His foundation is building a retreat in central Maine for other Veterans and was the raceís charity partner.