The event features ten kilometres of open water swimming followed by 65 kilometres of running and has been ranked as one of the toughest one-day races in the world.
One hundred and twenty teams of two from 22 different countries took part, with Lelle Moberg and Daniel Hansson finishing in 8 hours 16 minutes and 19 seconds.
From the start, the race was an exciting battle against last years winners Björn Englund and Paul Krochak, with the winning duo beating the previous record by 19 minutes, after setting off from Santahamina at 5:55am and finishing up on Utö.
Press manager Josephine Ås told The Local that the victors had benefited from a lack of wind and water temperatures of up to 12C.
"It was a really fast race and the competition was tough. We are seeing more prestigious competitors taking part each year," she added.
The annual Swimrun launched nine years ago after a group of friends came up with the idea following a few drinks.
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2014 marked the first time that organizers held qualifying races for the event, with one taking place in Sweden and another in the UK.
Those wishing to compete in 2015 can submit their entries from Thursday.