Colin O'Brien's team overcame Poland earlier in the week thanks to a single strike from Josh Giurgi, but they could not find a way past a skillful Belgium team in Marbella.
Thibo Baeten opened the scoring for Belgium on 22 minutes after he rifled a shot into the roof of Harry Halwax's net from close range.
Eight minutes later it was 2-0 to Belgium as Jean Pierre Longonda showed his composure to coolly slot a shot into the bottom right-hand corner of the net after a pass was pulled back to him at the edge of the penalty area.
Ireland continued to rally and their efforts were rewarded on 78 minutes when Omobamidele powered in a header after meeting an inswinging corner kick.
There was late drama in the 86th minute when substitute Ronan McKinley rattled the crossbar, but Ireland did not get that second goal that they craved.
Still it was a good test for a young squad as they continue their preparations for the U-17 European Championships in May.
Republic of Ireand: Harry Halwax (Jimmy Corcoran 46); Seamas Keogh, Luke Turner, Andrew Omobamidele, James Furlong, Thomas Considine (Sean McEvoy 46), Brandon Holt (Timi Sobowale 46), Joe Hodge, Toby Owens (Ronan McKinley 68), Conor Carty (Josh Giurgi 46), Roland Idowu (Matt Everritt 46).
Belgium: Stijn Cloodts; Hugo Siquet, Michael Davis, Heritier Bora Deyonge, Jeremy Landu, Maxime Cavelier, Samuel Asoma, Jean Pierre Longonda, Robbe Gheerardyns, Thibo Baeten, Wouter George.
Referee: Barbas Chamorro.