A last gasp 21-17 victory over the Dragons provided a winning start, but they were beaten 41-15 by the Scarlets at Stradey Park a week later.
The Dragons will be hoping to use home advantage when they take on a Blues South side who, like the Ospreys have won one and lost one of their opening two matches.
Tomorrow evening the Dragons under 18s travel to Llandarcy to face the Ospreys.
Blues South u-16: C Allen; H Robinson, J Morris, K Driscoll, M Roberts; R Patchell, T O'Brien; C Hole, P Lloyd, M Taylor, I Matthews, B Smith, E Chilcott, L O'Brien, R Tucker. Replacements: S Bennett, R Rowley, J Delf, R Phillips, S Vial, J B Bruziller, J Hurley.
Blues North u-16: C Edwards; O Rees, R Evans, T Pascoe, S Webber, L Williams (capt), D Evans, D Harris, J Dando, T Jones, A Lee, J Sieniawski, N King, J Perkins, W G John. Replacements: J Elley, C Waters, L Young, E Jenkins, L Jones, G Thomas, L Gunter.
Dragons u-18: W Jones; N Williams, M Jolly, J Daniels, L Folley; L Robling, A Jones; R Jones, M Webber, A Yule, R Wilson, T Crandon (capt), M Morgan, G Jones, C Howells. Replacements: L Jones, L Bacon, G Kemp, G Rogers, H Lewis, J Evans, J Merriman, A Norton, T Rusga.
There are more Blues age grade fixtures this week as the Under 18's take on Cardiff and District in a friendly, before the visit of Leinster on Sunday. This Welsh Irish age grade fixture follows the Blues U20's Victory over Munster, as the Blues continue to work in partnership with the IRFU and are the first to play two Irish age grade teams.