The head-to-head best of five was won after four matches as Finland's team of Silja Lehtinen, Silja Kanerva and Mikaela Wulff raced through one metre waves and swell in strong south-easterly winds into an unassailable 3-1 lead.
It was the Finns' second medal of the Games having earlier gained silver in the women's windsurfing RS-X event and fulfilled their promise of a year ago when Lehtinen led her team to victory in the Olympic test regatta in Weymouth.
The matches were raced on the shoreline Nothe course in front of thousands of spectators including an ecstatic flag-waving, face-painted bunch of Finnish supporters, enjoying the last day of the 2012 Olympic sailing events.
The Russian team of Ekaterina Skudina, Elena Siuzeva and Elena Oblova, who lost 2-1 to Spain in the reduced three match semi-final on Friday, were disappointed with their finish.
"It was our goal, our dream (to reach the final) so it is frustrating", Skudina said.
They were in second place going into the quarter finals behind the favourites from Australia.