A press conference was held this morning to publicise the deal, which will also deliver a TV, digital and mobile highlights offering.
All of the Ireland matches and final stages of the tournament will be broadcast free to air, with the tournament taking place in England and Wales from September 18th to October 31st 2015.
The deal is seen as a major blow to RTE, but comes after TV3 itself failed to retain its GAA package in the face of strong rivalry from the national broadcaster and Sky.
"TV3 is honoured to have been awarded these prestigious rights by the International Rugby Board,” said Niall COgley, TV3 Group Director of Broadcasting.
“We are quite sure that Rugby World Cup will be the stand out sporting event in 2015, which will anchor our 2015 Autumn Schedule.”
“As Ireland’s leading commercial broadcaster TV3 is building its strongest ever schedule of originated programming. The Rugby World Cup win is an endorsement of the strategy to invest in the most relevant content for Irish audiences and advertisers,” he added.
It is expected that the broadcaster will broadcast about 20 matches on TV3 and the remainder on 3e, although TV3 has not ruled out some sub-licenses to other Irish broadcasters.
Details regarding studio, commentary and touchline broadcast teams are yet to be finalised.