Touré left Manchester City at the end of last season after winning three Premier League titles, two League Cups and the FA Cup before rejoining the Greek giants on a free transfer.
However, the Ivory Coast legend failed to make an impact at Olympiakos with whom he won the domestic double in the 2005/06 season.
"Yaya is and remains an important member of the Olympiakos family, who has marked a central part of the history of the club," the club said in a statement.
"Olympiakos would like to thank him for everything he has offered to the club.
"Yaya will remain deeply devoted to the club and wishes to Olympiakos lots of success. Yaya is leaving as a friend and the doors at Olympiakos will always be open for him."