(Jacob Stockdale and Lorcan Dow)
Sam Arnold, Zack McCall, Alex Thompson and Lorcan Dow have all been named in the Ireland U20 starting XV for the opening game of the World U20 Championship, against Argentina tomorrow (kick-off 4.30pm local time/3.30pm Irish time, live on TG4).
Jacob Stockdale is also part of the squad and has been selected as a replacement.
Arnold starts at inside centre, with McCall named at hooker, Thompson selected in the second row and Dow picked at Number 8.
Joey Carbery will make his first start after four appearances off the bench during the Under-20 RBS 6 Nations. He takes over the out-half role vacated by his UCD and Leinster colleague Ross Byrne, who misses the tournament due to a back injury.
Carbery's inclusion is the only change to the back-line that started Ireland's last competitive game away to Scotland in March, with scrum half and captain Nick McCarthy earning his 16th cap at U-20 level.
Up front, there are two alterations with prop Oisin Heffernan (15 caps) and flanker Rory Moloney (9 caps) - two players who gained experience in last summer's Junior World Championship in New Zealand - both earning starting spots.
Charlie Rock and fellow uncapped half-back Tomás Quinlan, Byrne's replacement in the squad, could make their Ireland U-20 debuts off the bench, while fit-again hooker Sean McNulty, who played in the 2014 U-20 RBS 6 Nations, is back in the matchday squad.
Seven of the squad have previous U-20 Championship experience having played in the 2014 competition where Ireland finished fourth overall - Billy Dardis, Ciaran Gaffney, Heffernan, skipper McCarthy, Moloney, Josh Murphy and Garry Ringrose.
IRELAND UNDER-20 Team & Replacements (v Argentina Under-20s, 2015 World Rugby Under-20 Championship - Pool C, Stadio Sergio Lanfranchi, Parma, Tuesday, June 2, kick-off 4.30pm local time/3.30pm Irish time):
15. Billy Dardis (UCD/Leinster)
14. Ciaran Gaffney (Galwegians/Connacht)
13. Garry Ringrose (UCD/Leinster)
12. Sam Arnold (Ballynahinch/Ulster)
11. Stephen Fitzgerald (Shannon/Munster)
10. Joey Carbery (UCD/Leinster)
9. Nick McCarthy (UCD/Leinster) (capt)
1. Jeremy Loughman (UCD/Leinster)
2. Zack McCall (Queen's University Belfast/Ulster)
3. Oisin Heffernan (Terenure College/Leinster)
4. David O'Connor (St. Mary's College/Leinster)
5. Alex Thompson (Queen's University Belfast/Ulster)
6. Josh Murphy (UCD/Leinster)
7. Rory Moloney (Buccaneers/Connacht)
8. Lorcan Dow (Queen's University Belfast/Ulster)
Replacements:
16. Sean McNulty (UCD/Leinster)
17. Andrew Porter (UCD/Leinster)
18. Conan O'Donnell (Sligo/NUIG/Connacht)
19. Jack Dwan (UCD/Leinster)
20. Nick Timoney (St. Mary's College/Leinster)
21. Charlie Rock (Old Belvedere/Leinster) *
22. Tomás Quinlan (Cork Constitution/Munster) *
23. Jacob Stockdale (Queen's University Belfast/Ulster)
* Denotes uncapped player at international Under-20 level
WORLD RUGBY UNDER-20 CHAMPIONSHIP POOLS -
POOL A - England, France, Wales, Japan
POOL B - South Africa, Australia, Samoa, Italy
POOL C - New Zealand, Ireland, Argentina, Scotland
IRELAND U-20 FIXTURES:
Ireland Under-20s v Argentina Under-20s, Parma, Tuesday, June 2, kick-off 4.30pm local time/3.30pm Irish time (live on TG4)
Ireland Under-20s v Scotland Under-20s, Calvisano, Saturday, June 6, kick-off 4.30pm local time/3.30pm Irish time (live on TG4)
New Zealand Under-20s v Ireland Under-20s, Viadana, Wednesday, June 10, kick-off 8.30pm local time/7.30pm Irish time (live on TG4)
Match Day 4: Play-offs and semi-finals, Monday, June 15
Match Day 5: Play-offs and final, Saturday, June 20