The real deal may not take place until tomorrow morning - but that hasn't stopped one Dublin primary school from getting the marathon completed well in advance.
Pupils of St David's Boys National School in Artane run a relay marathon every year. This year, the 300-odd pupils got more than one completed as well.
Principal Dwain Moore said it's important for funding for the school and has also created great excitement among pupils.
"We give out sponsorship cards for the kids, they bring them home and we do it as a fundraiser for the school every year," he said.
"We set up a relay marathon so every child in the school ran a certain distance on Thursday and we added up the distances covered by everybody and it ended up as 23 marathons.
"There's 307 kids in the school so we mapped out courses with different distances - so we had courses of 100m and others of 150m. Basically each class had a half an hour slot - it's a great buzz," he added.
Mr Moore explained that he and one other teacher are set to complete the Dublin Marathon tomorrow for the school but he wanted to get the children involved as well.
"They all wanted to do as many laps as they could," he said.
"I went around to each of the classes after and they were all doing the sums on how far they ran to make up the marathon. There was actually learning in it as well - unintentional learning."
Elsewhere, Carlow man Paul Ward is putting his body on the line for a good cause by cycling to and from Dublin - and running the marathon in between.
The trained chef and a couple of helpers have already raised €5,000 for regional youth services in Carlow.
He's set to leave Carlow at 3.30am by bicycle, complete the marathon and then cycle back home again.
"We'll pull into St Stephen's Green at around 6.30am, we'll put the bikes into the back of one of the support vehicles, get changed and get breakfast at 7.30am," Paul said.
"We'll then make our way over to the start line, get stretched and warmed up, get the marathon done and then I will pull off at 2.30pm and cycle back."