The North, who welcome back captain Jack James amongst half a dozen others, are seeking a first away success of the season having beaten the Dragons, RGC 1404 and the Scarlets on home soil so far.
"It has been a really decent start for us, especially as we made a conscious decision to use every one of our squad members in the opening three weeks," said Blues North team manager Nigel Way.
"However, they don't come any more difficult than an away game against the Ospreys, so we will need to be at our best."
The Ospreys, having been pushed all the way by RGC 1404 and the Scarlets in their opening matches, swept aside Blues South last time out and will hope to make it four wins in four.
"From the moment the final whistle sounded last week, the boys have been looking forward to this one. It should be another great advert for the competition," said team manager Graham Court.
The other game at under 16 level sees the Scarlets take on the Dragons at Parc y Scarlets with the former seeking a first win in three games.
The Dragons, who have won two of their three games, are looking to build on their somewhat fortuitous 22-19 victory over RFC 1404 at Rydal School on Sunday.
At under 18 level, the unbeaten Scarlets make the long trip to Newbridge to face a Dragons side whose only game this term brought them a 27-16 victory in North Wales.
"It was disappointing when we lost our first game to the weather, but equally satisfying to go north and beat RGC 1404 with a bonus point," said Wayne Pugh, the Dragons' team manager.
They will have their work cut out against a Scarlets side for whom outside-half Jordan Williams has been in outstanding form.
"It's never easy to go to the Dragons and get a win, but we have started the season well and will travel to Newbridge with a degree of confidence," explained team manager Rob Evans.
The Dragons have plenty of fire-power behind the scrum with Luke Rogers, Hallam Amos and Mitch Starr the pick of an outstanding back line.
Last season's winners, the Blues, entertain the Ospreys at Cardiff Arms Park with both sides holding a 50 per-cent record.
The Blues, who kicked off the season with a 13-try beating of RGC 1404 at Merthyr, will be keen to hit back from their defeat against the Scarlets last time out.
The Ospreys, who lost to the Scarlets on the opening night, redressed the balance with a resounding 86-7 victory in North Wales.
Ospreys under 16: A Rowlands; A Bidwell, L Popham, J Thomas, D Howells; J White, T Maggs; L Jonathan, M Parmenter, G Stone, R Morgan, A Williams, J Davies (capt), C Leyshon, C Davies
Replacements:D Owens, C Forshaw, A Beard, J Collier, D Brooks, M Burnell, J Seldon
Blues North under 16: C Lawrence; J Barnett, A Summerhill, G Smith, S Edwards; J Evans; S Clarke; L Crump, A Gibbs, D Lewis, A Luxton, M Jeczalik, B Llewellyn, J James (capt), T Samuel. Replacements: N Evans, J Smedley, A Panniers, L Davies, J Harris, S Withers, G Davies
Dragons under 16s: M Starr (capt); J Rowley, H Amos, J Dixon, A Hewitt; L Rogers, L Crane; L Garnett, R Thomas, A Jefferies, J Bullen, D Jones, E Whitson, J Ford, R Pugsley
Replacements: K Ball, C Paul, T Sparshott, A Cullen, E Smith, T Senior, J Howell.
Scarlets under 16: J Evans; J Barnes, S Evans, C Woodall, M Davies; J Maynard, G James; B Davies, E Lewis, C Evans, J Helps, A Washbourne, L Watling, W Boyde, L Taylor
Replacements:D Thomas, C Davies, C Randall, T Phillips, G Kenniford, G Rees, J Adams
Dragons under 18s: L Morgan; J Casey, T Ashmead, S Cole, D Franchi; E Davies, J Davies; J Johnson, E Dee, D Goode, J Bartlett, L Randall, J Benjamin (capt), R Stephens, I Jones
Replacements: J Williams, B Edwards, J Everett, G Eldred, J Guy, N Martin, J Pursell
Scarlets under 18: L Treharne (capt); A Evans, S Hughes, D Jenkins, D Morgan; J Williams, C Lloyd; T Evans, T Ball, G Davies, C Morris, D Morgan, S Bennett, D Thomas, C Marks
Replacements: S O'Leary, T Kaijaks, J Williams, O Powell, R Williams, N Setaro, W Lewis
Blues under 18s: R Lovering; H Robinson, C Allen, R Evans, O Rees; R Patchell, L O'Brien; T Davies, J Hopkins, B Thyer, L Connolly, B Roach, J Sienawski, E Jenkins (capt), L Young
Replacements: E Lewis, J Dunning, Z Deere, S Pring, S Middlemiss, G Thomas, L Chalke
Ospreys under 18s: A Wellington; R Thomas, B Roberts, R Evans (capt), A Evans; S Davies, W Batcup; N Smith, E Yardley, D Suter, D Parry, R Hughes, RD Jones, E Williams, M Jenkins
Replacements: J Preddy, S Grabham, O James, M Davies, T Owen, S McRoberts, B Thomas, L Wilson