The 29-year old only signed a new three-year deal at Goodison Park in May.
"I really wanted to come to Olympiakos," Mirallas told Greek media following Belgium's 2-1 win over Greece.
"We tried our best to find a deal that would suit everyone, including President Vangelis Marinakis, who did everything possible and beyond - but Everton turned a deaf ear."
Mirallas has yet to start a Premier League game under manager Ronald Koeman this season.
"I am so sad that I have not been home and I hope that will be the case in the near future," he added.
"I would like to thank all Olympiakos supporters for the many messages they sent me. And they must know that I love their club and, as I said before, one day I will come back to them."