And it was the Ravenhill outfit who led the way in the regular season, finishing top of the table, three points clear of Leinster.
Glasgow Warriors finished third, two points behind Leinster, with the Scarlets taking the final spot in the top four after the Ospreys missed the chance to leapfrog them on the final day of the season.
However the Scarlets would not become the first team to win an away semi-final, going down in Belfast to Ulster.
In the other semi-final Leinster edged out Glasgow Warriors before going onto beat Ulster in the final in Dublin.
Early winners:
Ulster flew out of the blocks winning their first 11 games of the season to shoot to the top of the table, but they had to cope with tragedy after centre Nevin Spence was sadly killed in a farming accident in September.
A memorial service was held in Spence's honour, as the province paid tribute to the 22-year-old, who passed away along with brother Graham and father Noel in the accident.
They wouldn't lose a game until the final clash of 2012, a loss away to Munster.
Scarlets also started strongly, winning their first three matches, including successes against play-off bound pair Glasgow Warriors and Leinster before a derby loss to the Ospreys.
That was the Ospreys' first win after three defeats to kick off the campaign, and that would end up hurting them in the final shake-up.
The run-in:
It was all very tight heading into the last three rounds of the season, with Glasgow top of the pile, one point clear of Ulster, and Leinster two further back.
The battle for fourth was also going down to the wire between the Scarlets and the Ospreys, while Benetton Treviso - on their way to a best-ever finish of seventh - were trying to chase down Munster.
Round 20 would prove crucial as Glasgow went down away to the Scarlets, while Ulster and Leinster beat the Dragons and Munster respectively to move into the box seat for a home semi-final.
The top trio would win out, but it meant Glasgow were the ones left on the road in the last four.
In the race for fourth, the Ospreys' hopes all but disappeared with defeat in Glasgow in Round 21, coupled with a Scarlets victory at home to Cardiff Blues.
That meant that only victory away to Leinster would allow the Ospreys to sneak back into contention. They couldn't manage it, meaning that Treviso's bonus-point success in Llanelli didn't cost the home team.
The play-offs:
Having been the front-runners virtually all season, Ulster did likewise in their play-off semi-final, racing into an 18-3 half-time lead against the Scarlets.
Tries from Tommy Bowe and Robbie Diack set them on their way, with Tom Court's try straight after half-time seemingly putting the game to bed.
The Scarlets did fight back, with scores from Gareth Davies and then Sione Timani but it was too little too late as Ulster made the first final since the play-off system was reintroduced.
With just two points separating Leinster and Glasgow in the regular season, it was no surprise that their semi-final was a tight one.
Jamie Heaslip's try helped Leinster to an 11-10 half-time lead despite Niko Matawalu's early try.
However the boot of Jonathan Sexton kept the scoreboard ticking over for the home side with two more penalties.
Glasgow could have levelled the scores but after Mark Bennett's late try, Stuart Hogg's conversion, in windy conditions, drifted wide.
That set up a final between the top two, a week after Leinster had claimed the Challenge Cup title against Stade Français at the RDS.
They made the perfect start in Dublin, with a try from Shane Jennings after just three minutes.
Sexton, in his final game before moving to France, helped stretch the lead to 10-0.
Ulster were reliant on the boot of Ruan Pienaar, and he managed to cut the deficit to 19-15 on the hour.
However Heaslip's try put the result beyond doubt and secured the title - a fitting farewell for Joe Schmidt before he became Ireland coach.
Top scorers:
It might have been Jonathan Sexton's final season for Leinster, but it was teammate Ian Madigan who led the way in the point-scoring charts.
The young playmaker finished with 186 points, 14 clear of Ruan Pienaar, while Tom Prydie completed the podium.
The top try-scorer was less of a turn-up, as Tim Visser made it four straight seasons as the most prolific weapon in the league.
He finished with 11 tries for Edinburgh, one clear of Glasgow's DTH van der Merwe and Andrew Trimble of Ulster.
To buy tickets for the Guinness PRO12 Grand Final click here. Also follow us on Facebook, join the conversation on Twitter, sign up to our YouTube channel for extensive match highlights and sign up for our newsletter for regular updates on the Guinness PRO12.
63x46.png){kind=logo}