Frenchman Denis Chevrot has won the inaugural Ironman 70.3 Dublin in a time of 4 hours 1 minute and 35 seconds.
Susie Cheethman from the UK was the first woman to cross finish line.
All roads closures around Dublin ciyu centre have now been lifted following the event which continues through parts of Meath and Kildare until this afternoon.
Thousands of spectators turned out to watch the 2’500 triathletes compete.
Esther O Moore Donohoe from AA Roadwatch said traffic was now moving well around Dublin city centre.
Photograph taken from Air Support Unit of the swim stage from the Iron Man Dublin 2015 taken earlier this morning pic.twitter.com/qru6r1h4Si— An Garda Síochána (@GardaTraffic) August 9, 2015
Dublin City Council hosted the event which kicked off at 6.50am today.
More than 2,500 athletes completed the 1.2 mile swim in Scotsman’s Bay in Dún Laoghaire, before mounting their bikes to travel through Dublin and west of the city for a 56-mile cycle, to return to the Phoenix Park for the 13.1 mile half-marathon.
Update 15.28pm: Winner Denis Chevrot said he was was very impressed with his first experience of the Dublin course, saying: “It was a very fast course, with some great support and sights of Dublin along the route. I am very happy to have won Dublin’s first IRONMAN 70.3 race and look forward to racing here again in the future.”
Irishman and pro-triathlete Kevin Thornton, who finished in third place at a time of 04:08:34 said: “The atmosphere across Dublin today was just fantastic. To see so many people lining the streets on a Sunday morning to support everyone was just brilliant. It really helps everyone push themselves that bit harder.
“I set myself the target of a top three finish in the build up to the race, and I’m delighted to have claimed third place today, which even more special to achieve here in my home country.”