Division Three West outfit Dunvant presented a stern test at Broadacre but the north walians first half display gave them a 24-0 lead, although they were indebted to full back Carwyn ap Myrddin who landed a crucial three penalties to ease his side to a 30-24 victory.
Builth Wells of Two West were next up in the quarter-final and once again ap Myrddin was the star of the show with 13 points as Nant Conwy triumphed 18-13.
The semi-final was a tense affair against an Ystrad Rhondda side that ended the season as Division Two East champions.
Three penalties from ap Myrddin was enough to send his side to the Millennium Stadium after a nerve-tingling 9-3 victory.
"It means an awful lot to the club and we feel privileged to come down here to represent the whole of north Wales rugby," said Nant Conwy coach Alwyn Williams.
"It's been an up and down season but this is the pinnicle and can be the icing on the cake.
"This game is a huge bonus for us. We have a lot of people coming down from the Conway Valley, the club has sold over 1000 tickets which is massive for us."
Penallta of Division Two East rattled up the points on their way to the final.
Rhydyfelin fell 28-25 and Ynysybwl 32-9 taking the Pitmen into round four where a visit to Three East side Senghenydd, last year's SWALEC Bowl winners, awaited them.
A 22-3 victory at Welfare Park gave them a quarter-final tie against Three South West champions Maesteg Quins and tries from Andrew Jenkins and hooker Gregg Haynes eased Penallta into the semi-final after a hard-earned 18-8 success.
Bethesda of One North lay between Penallta and a trip to the Millennium Stadium and they made sure of a day out in the capital with a convincing 30-3 win, crossing for three tries.
"History has it we lost to Nant Conway in the Brewers Cup 12 years ago so we are out for a bit of revenge," said Penalta coach Matthew Tucker.
"It's the pinnicle of these guys' rugby careers - it's a dream to play here. To think the boys will be running out at the Millennium Stadium, where Grand Slams have been won is excellent. Hopefully there might even be one or two players coming back wearing a Welsh jersey in the future!
"The year so far has been overwhelming. We've had a three year plan to bring youngsters through our set-up. Out target was to finish in the top four of the league, we finished second and have got to a cup final. That's all to the credit of these youngsters, who have put in a phenomenal effort."