Sean Masterson with his brother, Connacht senior player Eoghan Masterson, after making his Ireland U20s debut.
The team will be coached by Kieran Campbell with Connacht Elite Player Development Officer Ambrose Conboy and Hugh Hogan the assistant coaches.
Corinthians' Masterson, who made his Ireland U20 debut against France last month, will pack down at number 8.
Exciting Marist College centre/full-back Reid has previously been involved with the Irish U18s and is named amongst the replacements.
The game concludes Japan’s Ireland-wide tour that began at Thomond Park last Wednesday, where a Munster U19 Development squad defeated their Far Eastern opponents 17-7.
The Japanese got their first win of the tour last weekend at the Sportsground, where they overcame the Connacht U19s 24-10.
Tonight they will play their third game of the two-week trip to mark the 60th anniversary of diplomatic relations between the two countries against Ulster at the CYIMS RFC in Belfast.
Ireland U19s to play Japan – Donnybrook Stadium, Saturday 25th March
15 Conor Wharton (Leeds Beckett University)
14 Mark Keane (Instonians RFC)
13 James Hume (RBAI)
12 David McCarthy (Garryowen RFC)
11 Peter Sullivan (St. Andrew’s College)
10 Michael Lowry (RBAI)
9 Hugh O’Sullivan (Belvedere College)
1 James French (Bandon Grammar School)
2 Diarmuid Barron (Garryowen RFC)
3 Tom O’Toole (Campbell College)
4 Matt Dalton (Belfast Royal Academy)
5 Jack Dunne (St Michael’s College)
6 Jack Cooke (London Irish RFC)
7 Aaron Hall (Ballynahinch RFC)
8 Sean Masterson (Corinthians RFC)
16 Alexander Clarke (Ballymena Academy)
17 Jordan Duggan (Naas RFC)
18 Bryan O’Connor (Presentations Brothers Cork)
19 John McCusker (Rainey RFC)
20 Max Kearney (Belvedere College)
21 James Kenny (Gonzaga)
22 Angus Curtis (Queen’s University RFC)
23 Corey Reid (Marist College)