More than 20,000 athletes are set to take on the 26.2 mile course this. The Dublin Marathon is fast approaching, with thousands of runners making their final preparations for the 42km race. On Sunday, October 25, 22,500 people will be striding through the streets. Dublin is set to be more chaotic than usual this bank holiday weekend as yet another storm blows in, the Dublin Marathon kicks off, and several rail services.