The talented 32-year-old - who has won 14 international caps for the Wallabies - has also had spells at Northampton Saints, where he won the English Premiership and European Challenge Cup, the ACT Brumbies and Western Force.
A destructive scrummager on the tighthead side - who stands 6ft 1in and weighs in at 293lbs -Ma'afu was part of the Australia squad that took part in the 2011 Rugby World Cup.
The front rower, who has Tongan and Fijian heritage, switched from rugby league to union as a youngster before climbing through the Sydney and NSW juniors ranks to make his Super Rugby debut in 2007 for ACT Brumbies. He also featured for Australia A later that year.
In 2010 he made his Test debut against Fiji, facing off against his younger brother, Campese, who himself is a former player at Cardiff Blues.
Head Coach Danny Wilson said: "We are thrilled to sign Salesi and welcome him to Cardiff Blues.
"Salesi is a powerful prop forward who will add to our set piece and enhance the front row options within the squad.
"He has a fantastic pedigree in the game, having won the English title and European honours during his successful time with Northampton Saints, and he is very keen to join Cardiff Blues and make a big impression at the region."
Factfile:
Full name: Ratu Salesi L. Ma'afu
Born: March 26, 1983, Sydney, Australia
Major teams: Brumbies, Force, Northampton Saints, Toulon, Australia
Position: Prop
Height 6ft 1in
Weight 293lb
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