Mouritz Botha has been reluctantly released by Saracens to join The Sharks in South Africa, with effect from January 1, 2015.
Mark McCall, Director of Rugby, said: "Mouritz has been a massive part of our squad and our culture for the past five and a half seasons, and we are very sorry to see him leave. However, this is a great opportunity to play for one of the top teams in the Super XV, and we wish him, Natasha and young Joshua well."
Botha joined Saracens from Bedford Blues in 2009, has played 142 matches for the club and has also been capped 10 times by England.
The blond lock forward, 32, said: "Saracens will always be important to me, and it’s difficult to leave so many friends in what remains a unique sporting environment, but the Sharks are trying to build something special in Durban. This will be a great rugby challenge for me, and a great adventure for my young family."