The cold did not put a stop to David O'Reilly yesterday as he threw himself into the Forty Foot before kicking off a charity walk to Galway to raise funds for Our Lady's Children's Hospital, Crumlin.
David (44) is embarking on the journey after seeing at first hand the care supplied by the hospital.
When he heard it receives no public funding for research and new equipment in the children's cancer ward, he decided he would do his bit.
"I was in Crumlin Children's Hospital last night and the mind boggles why there is no public funding for research and new equipment in a children's cancer ward," he told the Herald.
"Everything is privately funded. It's the same with the parents' accommodation there.
"I was privileged to get a tour by one of the patients' parents. It's really clean and quiet and well run by staff but all funded by businesses, individuals and families."
After his dip at the Forty Foot, David met students of CBC Monkstown at the east pier in Dun Laoghaire.
They shared the first steps of his 220km-plus walk to Galway to help him on his way.
"The walk is a day-by-day event and I've little planned in terms of accommodation or where I'm stopping," said David.
"If you were diagnosed with cancer as a child, it would be a serious journey into the unknown and a day-by-day event for yourself and your family.
"Comparatively speaking, I'm lucky to be going for a healthy walk in the park. I've seen people facing real challenges and they need our support.
"And it's great to see the lads from CBC Monkstown supporting Crumlin Children's Hospital. They're a solid bunch of lads.
"I'm looking forward to the journey this week and to meeting a few people along the way," he added.
To support David, donate at cmrf.org/user/david