Sykes, 26, joins from Super Rugby side the Sharks on a three-year deal and has represented South Africa at Under 19 and Emerging Springbok level.
"For me I believe it is a good career and personal move - I want to play international rugby and it would be a fantastic honour to play for Ireland as well if it came about. Before any of that though I am really excited to play for Leinster. I really do believe it is the right move for me," said Sykes.
"Of course it was not an easy decision to make, I don't for one second want anyone to think I am unhappy here or unhappy at the Sharks; I love the Sharks! I have played over 130 games for the Union and loved every minute of it. However I believe that it will be very good for my rugby to make the move and I am looking forward to the experience of playing in European conditions week-in and week-out, learning about their way of playing - which I think will suit me.


