The squad is in the Czech Republic for the three-match tournament, which will also see them take on the hosts and the USA over the course of the next four days, having travelled on Sunday.
Despite the strong score-line, today was a tough test for the side, as Belgium were on the front foot from the kick-off.
However, an excellent performance from goalkeeper Emma Ring and her defence, saw them shut Belgium out despite them looking the stronger side.
And two goals from Ellen Molloy in the 24th and 39th minutes saw Ireland in front at the break - the young Thomastown United player took advantage of a free-kick and an opposition mistake to bag her goals.
Not long after the restart, Erin McLaughlin put Ireland 3-0 up on the 49th minute, and Kerryanne Brown got number four on the 80th minute, having had a few chances to get on the scoresheet.
In line with the rules of the UEFA Development Tournaments, all 20 squad members got a chance to play in the tie, with preparing players ready for competitive international football being the main aim of the fixtures.
Under-16s manager Sue Ronan explained that it was a very challenging game for the players, despite what the score-line might suggest.
“I’m really delighted with the result. We were under a lot of pressure in periods of the game, particularly the first 15 to 20 minutes. They looked very fast and fit and we knew we were up against a good side. But we stuck at it and defended very well and they didn’t manage to take advantage. Our goalkeeper, Emma Ring also made some excellent saves, she had a great game,” said Ronan.
Ronan added that the tournament is of huge benefit to the players and that could be seen in the game by the way they reacted to being involved in such a tough test.
She said: “From our solid defensive start, we grew in confidence and got two goals before the break. They were always dangerous going forward and we were out of position for much of the game, so we are really happy that we got the result we did, adding to those two first half goals with two more in the second half. It’s a quick turnaround now before the next game, which is in 48 hours, so we’ll move on to preparing for that straight away.”
Starting 11: Emma Ring (Peamount United), Shauna Brennan (Galway WFC) (pictured), Jessica Stapleton (Cherry Orchard), Della Doherty (Peamount United), Aoibheann Clancy (Limerick), Teegan Lynch (Sion Swifts), Ellen Molloy (Thomastown United), Rebecca Watkins (Peamount United), Emer O'Neill (Sligo Rovers), Aoife Horgan (Limerick), Anna Fahey (Galway WFC).
Substitutes: Rugile Askalnyte (Bohemians), Therese Kinnevey (Galway WFC), Chellene Trill (Galway WFC), Kate O'Dowd (Sligo Rovers), Muireann Devaney (Sligo Rovers), Erin McLaughlin (Sea Rovers), Zoe Leonard (Shelbourne), Hazel Cawley (Peamount United), Kerryanne Brown (Sion Swifts).
UEFA Women's Under-16 Development Tournament
May 21, Republic of Ireland 4-0 Belgium 13:30 CET, Pratelstvi Stadium
May 23, Republic of Ireland v USA 13:00 CET, Pratelstvi Stadium
May 25, Czech Republic v Republic of Ireland 11:00 CET, Rosického Stadium