Tiernan O’Halloran comes in at full back with Craig Gilroy moving to the wing. JJ Hanrahan who came on as a replacement against England now starts in the centre partnership with Brendan Macken.

James McKinney has been promoted to the starting XV also, taking over at outhalf from Paddy Jackson who moves to the bench.

Daniel Qualter has been named alongside Michael Kearney in the second row with Aaron Connelly making his tournament debut in the back row.

Iain Henderson, Dominic Gallagher, and Luke Marshall have been named in the replacements.

Speaking about his selection, Ruddock said "We have looked closely at South Africa and they present another massive challenge. Typically they are a big and very physical side. Combine that with a four day turnaround and it is important that we introduce some freshness into our team. As such I have made five changes to the team that played England. The players coming in are all experienced age grade internationals and they will be keen to perform on the big stage."

Ireland Under 20s play South Africa Under 20s in Treviso this evening at 8.10pm (7.10pm Irish time), the game will be televised on Sky Sports 3.

Ireland Under 20 Squad:
15 - Tiernan O’Halloran (Galwegians - Connacht)
14 - Andrew Conway (Blackrock - Leinster)
13 - Brendan Macken (Blackrock - Leinster)
12 - JJ Hanrahan (UL Bohemians- Munster)
11 - Craig Gilroy (Dungannon - Ulster)
10 - James McKinney (Queens - Ulster)
9 - Kieran Marmion (UWIC - Exile)
1 - James Tracy (UCD - Leinster)
2 - Niall Annett (Belfast Harlequins - Ulster)
3 - Tadhg Furlong (Clontarf - Leinster)
4 - Michael Kearney (Clontarf - Leinster)
5 - Daniel Qualter (Buccaneers - Connacht)
6 - Jordi Murphy (Lansdowne - Leinster)
7 - Aaron Connelly (Galway Corinthians - Connacht)
8 - Eoin McKeon (Galwegians - Connacht)
Replacements:
16 - David Doyle (UCD - Leinster)
17 - Conor Carey (Ballymena - Ulster)
18 - Iain Henderson (Queens - Ulster)
19 - Dominic Gallagher (Dublin University - Ulster)
20 - Peter Du Toit (UCD - Leinster)
21 - Paddy Jackson (Dungannon - Ulster)
22 - Luke Marshall (Ballymena - Ulster)

Ireland Under 20 Pool Games (All Times are Local)
14 Jun 20:10 Ireland v South Africa Stadio Comunale di Monigo, Treviso
18 Jun 20:10 Ireland v Scotland Stadio Mario Battaglini, Rovigo