Dolgellau got off to a wonderful start, scoring three tries in the first 25 minutes by showing some great support play amongst the backs.
Two tries were scored by Jess Kavanagh, and another by Elen Evans, all converted by Lowri Evans.
Waunarlwydd then stepped up a gear and following a five metre scrum, prop Carole-Anne Burt easily scored a try which went unconverted for the score to remain 21-5 at half time.
The first 15mins of the second half was a tussle amongst the forwards which was exactly what Dolgellau didn't want as the opponents were a much larger pack.
However, Dolgellau's ever present full-back Emily Oliver scored a well deserved try which was once again ably converted by Evans.
The final 20 minutes of the second half was completely dominated by Waunarlwydd with Dolgellau picking up two yellow cards for repeated infringements, and Waunarlwydd also going down to 14 players following a yellow card.
Due to some excellent support play Waunarlwydd added more points to the score sheet when fly half Siwan Lillicrap broke through the defence and scored the final try of match.