Inst showed their powers of recovery as they battled from 14-5 down to reach the showpiece decider on St Patrick’s Day.
Campbell already clinched their final spot on Monday as they narrowly beat Methody College in a nail-biting clash.
RBAI have won the competition 34 times, with only Methody (37), lifting the famous trophy more.
They were last in the final back in 2024 when they beat Ballymena Academy to make it two wins in a row.
Here’s all the best images from RBAI’s semi-final clash against Ballymena Academy, courtesy of Pacemaker.
1. SCHOOLS' CUP
RBAI players celebrate after reaching the Schools' Cup final Photo: Pacemaker
2. SCHOOLS' CUP
RBAI’s George Gamble and Ballymena Academy’s Ross Dillon pictured in action during Wednesday’s game Photo: Pacemaker
4. SCHOOLS' CUP
RBAI’s Charlie Hargy and Ballymena Academy’s Ross Dillon pictured in action during Wednesday’s game Photo: Pacemaker