More than 22,500 entrants, including elite athletes, club runners, wheelchair participants and charity fundraisers, are due to participate in this year's Dublin Marathon.
A number of road closures and diversions will be implemented across the city ahead the 44th edition of the event, which is due to get under way at 8.45am and finish any time up to 5pm.
Around 330,000 spectators are also expected to gather on the streets to watch the race.
The Irish Life Dublin Marathon starts on Leeson Street Lower and will be overseen by more than 200 volunteers on the route, which traverses Dublin city centre, the Phoenix Park and around University College Dublin, ultimately finishing on Mount Street Upper.
Last year, a UCD study found the marathon had generated almost €24m for the economy across hospitality, accommodation and local businesses.
This year, €9m is projected to be raised for more than 120 charities.
The first elite athletes are expected across the finish line around two hours after the race starts.
The Lord Mayor's Medal will be presented at the start line to 85 year-old Kevin Stynes from Dublin in recognition of his participation in 42 marathons in a row and fundraising efforts for Down Syndrome Ireland.
Speaking about the award, Lord Mayor of Dublin Councillor Ray McAdam said Mr Sytnes "epitomises the true spirit" of the marathon.
"His lifelong dedication to supporting Down Syndrome Ireland through his marathon running is nothing short of inspirational," he added.
Mary Nolan Hickey, the only woman to have run every marathon until last year, will present a new perpetual cup named in her honour to the winner of this year's women's elite race.
The race's organisers have warned there "may be some delays to public transport services" to facilitate the marathon, urging people to allow extra travel time.
Luas has said there will be a "temporary partial closure" on its Red Line Service.
It said no tram will operate between Heuston Station and Connolly station from 08.45am to 10.45am, however, services will run between Tallaght/Saggart and Heuston during this period.
Dublin Bus said a number of diversions will be in place across several routes from early this morning.
