Behind the scrum, Scarlets full back Daniel Evans returns to the starting line-up in place of Jason Tovey and Nathan Rees starts on the left wing in place of Jimmy Norris.
In the forwards, Rhys Lawrence and Patrick Palmer get a chance to start at hooker and tighthead respectively, while north Walian Haydn Pugh returns to the second row ahead of Ashley Sweet. Lloyd Phillips returns at no 8 with Josh Turnbull moving to his preferred position at blindside flank in place of Justin Tipuric.
"Our selection policy throughout this Six Nations campaign is to give everyone a fair chance at staking a claim for a place in the Wales squad for the Junior World Championship in June," said Horgan.
"Jason Tovey had an excellent game at full back against Italy, but so did Daniel Evans against Scotland so it's a case of everyone getting a fair amount of exposure.
"Nathan Rees has impressed in training and for Cardiff in the Principality Premiership so he has a chance to show what he can do, in this case in place of Jimmy Norris. Rhys Lawrence is in a similar position at hooker where we are likely to only have two places in our 26-man Junior World Championship squad so he deserves a chance to shine.
"It's good to see Patrick Palmer and Lloyd Phillips have worked their way back into the starting line-up after injuries but Scott Andrews and Justin Tipuric have made a mark in their absence and I'm sure they will make an impact at some point in the game."
"Ireland, like us, have recorded home wins over Scotland and Italy and will be looking to build on those results.
"They are very powerful up front and have an excellent scrum.
"It's important we get a win away from home to see the quality we've got in this squad, while also trying to develop the group of players for the forthcoming World Championship."
Wales Under 20 v Ireland, Friday 7 March, 7.35pm, Dubarry Park, Athlone:
Daniel Evans (Scarlets); Leigh Halfpenny (Blues), Jonathan Davies (Scarlets), Gareth Owen (Ospreys), Nathan Rees (Blues); Daniel Biggar (Ospreys), Rhys Webb (Ospreys); Ryan Bevington (Ospreys), Rhys Lawrence (Ospreys), Patrick Palmer (Blues), Jevon Groves (capt, Blues), Haydn Pugh (Scarlets), Josh Turnbull (Scarlets), Nicholas Cudd (Scarlets), Lloyd Phillips (Scarlets).
Replacements: Sam Hobbs (Blues), Ryan Prosser (Bristol Academy), Scott Andrews (Blues), Ashley Sweet (Dragons), Justin Tipuric (Ospreys), Luke Evans (Blues), Rhys Williams (Scarlets)