The Sky Blues have captured the 31-year old after his one-year deal with Melbourne Heart expired recently.
"I'm thrilled to be joining Sydney FC," Garcia said.
"Sydney FC is a big club with big expectations and that's something I thrive on. To be playing alongside players like Alessandro Del Piero, Brett Emerton and Nick Carle will be a fantastic experience for me and something I'm very much looking forward to.
"I can't wait to start pre-season training with the team and I look forward to working hard with the rest of the boys to win a spot and then helping Sydney FC push for success this season."