The Arms Park youngsters will start the game as favourites after defeating the Welsh All Blacks in two league clashes and Cardiff secured the league title last weekend after their 26pts to 20 win over Bridgend.
Neath are battling for the runners up position but will be looking to deny the Arms Park side an unique league and cup double in the competitions inaugural final.
Ryan Williams starts at scrum half partnering Dylan Pugh, who contributed so effectively to the semi-final success away to Pontypridd. Wing Andrew Jones returns while the pack remains unchanged.
Cardiff show just two changes from the side which defeated Llanelli in the last round with Darren Ryan selected at centre and lock Tait returning to the side after his recent run in the senior side.
Neath U'21s: P.Thomas, R.Carter, M.Jones, P.Smiriglia, A.Jones, D.Pugh, R.Williams, P.James, A.Matthews (capt), A.Jones, G.Evans, L.Bassett, S.Peters, D.Evans, S.Phillips
Cardiff U'21s: C.Anderson, E.Jones, O.Ashman, D.Ryan, G.Williams, N.Macleod, C.Miller (capt), J.Yapp, K.Jarma, D.Evans, L.Tait, C.Stamatakis, J.Malpas, M.Leach, M.Leaman
After two years in the international wilderness, Adi Taviner is hoping to make up for lost time when she takes part in her second Women's Rugby World Cup which kicks off in Paris next Friday where Wales take on hosts, France.
The WRU's Women and Girls legacy events - #TRY OUR GAME have proved popular this week with current players and newcomers to the game learning new skills and picking up tips from national squad players.
We caught up with Shona and Ellie from the Wales women team ahead of the start of the Women's Rugby World Cup in Paris next month at a recent women's training session to encourage and promote more women and girls to try their hand at rugby. #tryourgame
The Women's Rugby World Cup warm-up clash between Wales and USA proved bittersweet for centre Elen Evans. Despite being one of the star performers on the day on her 50th Test appearance, USA edged home 10-7 at Cross Keys.
Wales completed their Junior World Championship campaign with a victory over Samoa. Team manager Mark Taylor and No 8 James Benjamin reflect on a tournament which saw Wales win three games and lose two.