For the Scarlets, victory over their closest rivals will also suffice - their recent run of fine results has left them on the verge of a place in the final against the outstanding Blues South side which has already completed their league games.
In the other game on the night, Blues North take on the Dragons at Aberdare. Competition ambassador Rob Howley said, "The U16 competition has been as eagerly contested as the U18 and U20 competitions. For the whole season to go down to the wire shows you just how competitive things have been."
Meanwhile the U18s of the Ospreys and Scarlets are in action this Saturday in the U18 WRU Regional Championship final at the Millennium Stadium (kick off 1pm).
Scarlets: D Evans; G Peachment, R De Fillipo, A Jones, M Lemon; D Newton, M Gibson; R Jones, R Guest, K Jones, L Jones, H Pugh, J Spurway, N Cudd, M Evans. Replacements: R Lane, D Watts, T Wyn, D Jenkins, M Williams, N Murphy
Ospreys: L Halfpenny; N Hopson, T Williams, S Soul, L Osowicz; D Biggar, M Schopher; R Bevington, O Phillips, P Price, J Richards, J Griffiths, J Shaw, S Evans, A Bale Replacements: R Webb, S Davies, L Phillips, D Ronan, C Kelly, S Jones, N White
Dragons: J Tovey; G Dare, M Williams, D Jones, N Jones; D Langdon, J Leadbeater; J Wilkins, L Harwood, M Lear, M Witts, A Sweet, A Phillips, S Horton, M Williams Replacements: S Ford, L Cale, J Burgess, I Thomas, D Reeks, O Davies, N Buck