The 27-year old will join the Mariners for the remainder of the season after falling out of favour in Perth and admitted he was delighted to have joined the Gosford club.
"When I started in the first season with the Roar, the Mariners were keen to have me here and I was looking at it," he said.
"The Mariners have always been a club that have been developing and now when I've been away and come back I can look at the Mariners as a big club in Australian football. They are only going to go up in leaps and bounds and I want to be a part of that."
Bair, who made 13 appearances for the Glory scoring just the one goal, received the best wishes of head coach Ian Ferguson upon his departure.
"I wish Michael all the best with the Mariners and appreciate the contribution he's made for Perth Glory this season," Ferguson said.
Baird will be eligible for this Sunday's clash with Wellington Phoenix at Bluetongue Stadium.