Wilkshire, 35, was a free agent after most recently playing for Dynamo Moscow in his second stint for the club. 

The defender also played for the Russian club between 2008 and 2014, after stints at Middlesbrough, Bristol City and FC Twente. 

After leaving Dynamo in 2014, Wilkshire spent with with Feyenoord in the Netherlands, before returning to Russia with Terek Grozny and later re-joining Dynamo. 

It will be the right-backs first time playing for an Australian club in almost 20 years, an opportunity he said was too good to turn down. 

“I’ve spent a lot of years playing my football outside of Australia, and like many Australians playing overseas who have never played in the A-League, I have always wanted to come back at some point and experience the competition," Wilkshire said.

"I’m aware, and impressed by, the standard of the league from what I’ve seen from abroad, so I take nothing for granted.

“A big factor in my decision to join Sydney FC amid other interest, is my relationship with [Sydney FC coach Graham Arnold] Arnie. He was part of the coaching staff when I began my Socceroos career and he has done a great job with Sydney FC, so I’m really looking forward to working with him again. 

"I also have Socceroo friends in the squad in Dave Carney, Alex Brosque, Josh Brillante and Alex Wilkinson."

Wilkshire is a solid replacement for Rhyan Grant, who will miss the entire season after suffering an ACL injury.