Cavendish, a charismatic and at times nervy rider who took the green jersey as the Tour's leading sprinter in 2011, has 26 stage wins to his name.
The South Africa-based team, to be known as Team Dimension Data next season, said it was also hiring Australian Mark Renshaw and Austrian Bernhard Eisel, two former teammates of Cavendish who will be tasked with setting him up in the sprints in next season's races.
Cavendish, who is joining from Etixx-Quick Step, won the road race at the world championships in 2011.
"I’m super excited about becoming a part of the Team for 2016," Cavendish said in a statement. "It is a team that I have watched closely as it has grown, especially over this season and been really impressed with the spirit, strength and dynamics of the group."
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Cavendish had a difficult 2015, whose highlight was a single stage win on the Tour before he withdrew from the world championships following surgery on a shoulder he damaged in a crash during the Tour of Britain.
His presence, however, will give a media boost to Dimension Data, for whom fellow Briton Stephen Cummings won a Tour stage this year.
"Mark Cavendish joining our team is a huge step forward for the team as we strive to get to the next level in world cycling," team owner Douglas Ryder said.
"To also integrate Mark Renshaw and Bernie Eisel is a game changer in terms of performance and experience."
(Reporting by Julien Pretot; editing by John Stonestreet)
