In 2012, Alan Corcoran raised €15,000 by running 35 marathons in 35 consecutive days around the Irish coastline.
He donated the proceeds to the Irish Heart Foundation, after Alan's father Milo, a former FAI president, suffered a stroke in 2011.
Milo Corcoran passed away from cancer last year, and one month after Alan got into the water and started training.
Alan is swimming 500km around the Irish coastline.
He is going to swim up to ten hours a day and cover more distance than an Olympic Marathon in each swim until the 500km is completed.
"It'll be a kilometre at a time until I get home," he said.
Visit marathonman.co to find out more or make a donation.
All of the proceeds from Alan's swim will be donated to the Irish Heart Foundation and Solas Cancer Support Centre.