Ciarán is a gardener by trade but come the 14th of July this year, he will become an elite runner as he takes on his challenge across the country.
Starting at Bray Head on Valentia Island Ciarán hopes to make it to the finishing line at Marlay Park, Dublin, in just 9 days. That's 66km a day!!
On this morning's Dermot and Dave, Muireann gave him a call to find out all about the mission he has set himself and why he has chosen the Irish Society for the Protection of Cruelty to Animals.
Not bad going for a man who hated running not too long ago.
Take a bow (wow) buddy.
To check out more on Ciarán's trip and find out how you can donate - click here.
You can listen to the chat in full by pressing the play button in the image at the top of the page.