Dolgellau's 28-5 home win over COBRA took them 10 points clear at the top of the SWALEC Division 2 North table with one game left to play, making it impossible for them to be caught.
And Shotton Steel took the SWALEC Division 3 North crown as they maintained their unbeaten run with a 39-14 home win over Llangollen. Having finished as the runner-up in the league last season, they made no mistakes this season.
SWALEC are the national community partner of the Welsh Rugby Union, having signed a deal that saw the company become national sponsor of both the SWALEC Leagues and SWALEC Cup, Plate and Bowl competition in 2008. In 2011 they signed a four-year extension.
Over the next few weeks the champions of the remaining 22 SWALEC National Leagues will be crowned with presentations and celebrations the length and breadth of Wales. SWALEC Rugby Ambassador, triple Grand Slammer Ryan Jones, was among the first to congratulate Dolgellau and Shotton Steel and to acknowledge their achievement.
"Winning a league title takes a lot of unseen hard work around a club and it is not just the players who should be congratulated for the success. The coaches, medical teams, club committees, bar staff and tea ladies all play key roles in the success of a club," said Jones.
"I know exactly what it feels like to be part of a winning team. Winning a third Grand Slam with Wales this season was a very special feeling, but no greater I'm sure than everyone at Dolgellau and Shotton Steel RFC will be feeling in the wake of their success in winning the SWALEC Division 2 and 3 North titles.
"You win titles through good planning, consistency, camaraderie, determination and skill. Then you have to go and do it all over again next season. This is just the beginning and the real test will come in next season's SWALEC National League campaign. Good teams win titles, great teams keep on winning them."
Dolgellau coach David Owen was delighted to see his side run out winners at Parc Menter Marian Mawr at the weekend and they can relax and enjoy their final league outing against Rhyl at home this Saturday. They have scored 73 tries throughout the league campaign and lost only once at Machynlleth way back in October.
"Winning this title means an awful lot to a club like Dolgellau. We are only a small community club and a lot of people put a lot of time and effort in and the reward for everyone's hard work is winning this title," said Owen.
"It is testament to all the hard work the boys have put in on the field and they do deserve this. We have had to learn some hard lessons in recent seasons and we realised we couldn't afford any slip ups early on or in the middle of the season.
"We have been doing well for a few years now and this just recognition for all the hard work the players have put in. But the challenge for us is to show we can compete in Division 1 North.
"We have only lost one game all season and we really shouldn't have lost that but we have tried to play open rugby all season and Ian Morris our wing has scored 17 tries and is the league's leading try-scorer this season.
"That shows the type and style of game we are trying to play and I would like to think the players enjoy it and we have shown you can win a title by playing like that. Now we have to prove we can do the same at a higher level."
Shotton Steel's took their points tally up to 946 and their try count to 133 with their victory over Llangollen - and made it a perfect 17 from 17 in SWALEC League Division 3 North. Skipper Mark Higgins led by example throughout the season and can't wait to have a crack at a higher level.
"It's a fantastic achievement for the club and is recognition of all the hard work everybody has put in over the last few years. We have had back-to-back promotions and now we will be playing in Division Two next season and we are really looking forward to that," said Higgins.
"We have only lost one game all season, and that was in the cup, but we have set ourselves the target of going through the whole league season unbeaten. We want to keep our winning record and that is the aim for the rest of the season.
"We have set ourselves the challenge of scoring 1,000 points for the season and we are only something like 60 points away from that and we have set our sights of reaching that milestone too.
"I was looking at all the leagues in Wales the other day and we have scored more points than any other club in Wales and we have the third best defensive record, which is a helluva achievement for a club like Shotton.
"We were regarded as just a pub team a few seasons ago and this shows how much we have all pulled together. We have given players from our youth section a chance and have a very young side and now we have given ourselves the chance of playing at a higher level next season."