Meanwhile the Under 18s, who have already qualified for next month's final, also rattled up a victory - they ran in 10 tries in beating Gogledd Cymru 66-0.
Sam Hughes (2), Jamie George (2) and Gareth Harvey were amongst the try scorers as the North slipped to another away day defeat. The side will now meet the Scarlets in the final at St Helens, Swansea.
The Scarlets Under 16s need to beat the Dragons at Tredegar this evening to keep alive their hopes of reaching the final.
However, the Dragons will be no pushovers on home soil and will hope to spoil the visitors' party and avenge the defeat they suffered earlier in the season.
Scarlets: G Rees; G Hunter, L Harvatt, M Jenkins, P Rushesha; J Williams, S Maynard; N Bowen, S O'Leary, S Lee, D Evans, D Evans, J Gardiner, R Bloomfield, O Powell, C Morris. Replacements: A Williams, D George, C Evans, G Comley, R Evans, R Williams, N Stearo.