Trimble, D'Arcy get World Cup chop
The 30-year-old had missed this years' Six Nations through injury but had returned to action this year and was available for the global showpiece.
Trimble has played just once for Ireland in the past 12 months, a 35-12 victory over Wales in a World Cup warm-up match on August 8, but a flare-up of his toe injury meant he played only 33 minutes of that game.
Wings Keith Earls and Luke Fitzgerald, who were injured during Saturday's Dublin defeat by Wales, are included the squad.
Trimble, Gordan D’Arcy, Kieran Marmion were notably the most high profile players to miss out on the plane.
D'Arcy's omission could signal the end of his illustrious international career.
The squad is made up of 17 Forwards and 14 Backs and will be captained by Paul O'Connell who is the most capped player in the Ireland group with 103 caps.
Seventeen players will make their tournament debuts at the World Cup – Darren Cave, Luke Fitzgerald, Tadhg Furlong, Iain Henderson, Chris Henry, Robbie Henshaw, Paddy Jackson, Dave Kearney, Ian Madigan, Jack McGrath, Jordi Murphy, Peter O'Mahony, Jared Payne, Richardt Strauss, Devin Toner, Nathan White and Simon Zebo.
Ireland head coach, Joe Schmidt, confirmed that the process of selecting the squad was a difficult one.
"The players have worked incredibly hard over the past two months. Sunday was a difficult and very long day for the coaching team and an anxious one for many players," said Schmidt.
"There were some very tight decisions, particularly in the back three and it was also a challenge to make sure that key positions were covered as much as a squad of 31 players allows.
"A number of players were very unlucky to miss selection. We know from observing past World Cups that it's important for us to keep track of their performances because some of them are likely to be involved in the tournament."
Ireland are in Pool D alongside Canada, Romania, Italy and France and the men in emerald green's first game of the tournament comes against the Canadians at the Millennium Stadium Cardiff on Saturday September 19.
Ireland World Cup squad:
Forwards: Rory Best, Sean Cronin, Tadhg Furlong, Cian Healy, Jamie Heaslip, Iain Henderson, Chris Henry, Jack McGrath, Jordi Murphy, Sean O'Brien. Paul O'Connell (captain), Peter O'Mahony, Mike Ross, Donnacha Ryan, Richardt Strauss, Devin Toner, Nathan White.
Backs: Tommy Bowe, Darren Cave, Keith Earls, Luke Fitzgerald, Robbie Henshaw, Paddy Jackson, David Kearney, Rob Kearney, Ian Madigan, Conor Murray, Jared Payne, Eoin Reddan, Jonathan Sexton, Simon Zebo.
