Mike Phillips has been reinstated at scrum half with Dwayne Peel moving to the bench in the only change to the back division, meaning Stephen Jones is set to win his 69th cap boasting an all-time points tally just 5 points short of the 600 mark.
In the front row both Huw Bennett at hooker and prop Adam Jones are recalled and Alun-Wyn Jones has recovered from injury to take up his place in the second row in the final change to the starting line-up.
On the bench Duncan Jones and Matthew Rees provide front row cover with Rhys Thomas missing out, Ian Evans edges out Deiniol Jones and Gareth Delve retains his spot. James Hook and Sonny Parker join Peel to provide cover for the backs.
"A number of players have had a run-out for us in the first three games of the championship and selection in most areas could be put down to the toss of a coin which is testament to the effort the guys have put in," said Gatland.
"We've had to make a judgement call at scrum half, in the front row and in the second row, but it really is a close call for us in each of those positions as well as elsewhere in the team.
"Ireland are a fantastic side, they've been a top five team in World rugby for a number of years and we have an opportunity to measure ourselves and find out where we are.
"We go there as underdogs, they have lost only one game themselves in the dying minutes against France and Croke Park will be an intimidating place, but we must not be daunted by the task at hand.
"You only have to look at the number of caps they have throughout the side to recognise they will be a major force to be reckoned with and in Ronan O'Gara they have someone who can direct the game and really hurt opponents.
"If we don't keep a tight rein on him it could be a long day for us. We will be showing Ronan and his side the utmost respect.
"We are in a great position going for a triple crown, it would be nice, but the most important thing to us is the championship. The Triple Crown would be the icing on the cake, but at this stage we just need to make sure our performance is where we want it to be and take it from there."
Shane Williams has scored 10 tries in his last seven Tests and needs one try to equal Gareth Thomas's Wales record of 40 tries.
WALES: Lee Byrne; Mark Jones, Tom Shanklin, Gavin Henson, Shane Williams; Stephen Jones, Mike Phillips; Gethin Jenkins, Huw Bennett, Adam Jones, Ian Gough, Alun-Wyn Jones, Jonathan Thomas, Martyn Williams, Ryan Jones (Captain)
REPLACEMENTS: Matthew Rees, Duncan Jones, Ian Evans, Gareth Delve, Dwayne Peel, James Hook, Sonny Parker
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