Yosef Mahdy opened the scoring for Limerick — who were beaten twice in the league by Cork this season — from a 22nd minute Declan Cusack through ball in an entertaining final.
Sean McSweeney and Ross Mann went close for Tommy Barrett’s side after Mahdy struck, with Tommy Holland saving well from Cork’s George Gill and Connor Ellis at the other end.
Aaron Drinan took advantage of poor defending to restore parity 10 minutes after the break, and Holland denied Ellis minutes later.
Holland saved from Denzil Fernandes 15 minutes from time, but Ellis picked himself up after being upended by Killian Brouder minutes later to fire home a penalty.
Brouder almost made amends that foul on the stroke of full time, but his header was well saved by Coffey.
Ellis scooped the man of the match award.
Shamrock Rovers face St Patrick’s Athletic in the U17 final at Oscar Traynor Centre, Coolock tonight.
The games kicks off at 7:30pm.
Holland, Lowth, McCartan, Brouder, O’Connor, O’Connell, Cusack (Fitzgerald 61), Mann, Mahdy (Haverty 83), McSweeney, Kelly (E Cusack 68).
Coffey, Taylor, Manley, McCarthy, Coleman, Gill, Cronin (Fernandes 66), Donnellan, Ellis, Drinan (Byrne 83), Ogrene.
R Hennessey (Limerick)