In the WSRU Senior Group final, Ysgol Bro Morgannwg, of the Vale of Glamorgan, take on Llanishen High School of Cardiff, with the match kicking off at 2.45pm.
Cardiff Schools will take on Rhondda Schools in the Dewar Shield Final, with both teams aiming to get their hands on the prestigious trophy.
Speaking ahead of the matches, Richard Hodges, Blues Community & Coach Development Manager said, "The fact that there are four teams from the Blues region contesting in national finals is testament to all the hard work put in by coaches and teachers, and of course all the effort of the players competing."
"Without the grass roots work put in by them we would not be able to develop the future rugby players for the Blues and Wales."
"Wednesday promises to be a fantastic day for all the youngsters taking part and we wish all teams the best of luck."
2.45 pm WSRU Senior Group Cup Final-Ysgol Bro Morgannwg v Llanishen HS
4.45 pm Dewar Shield Final-Cardiff Schools V Rhondda Schools.