After spending six weeks in hospital being treated for anaemia, parasites on his skin and a head injury, Jervis the 100kg green turtle is finally heading home.
The sea reptile was found washed up at a beach on the South Coast in May.
He spent a month and a half recovering at Taronga Wildlife Hospital and was released into Sydney Harbour on Thursday.
"He was very sick," Taronga senior veterinarian Dr Larry Vogelnest said.
"But thankfully he recovered quickly."
A small green turtle named Wanda was released alongside Jervis just outside Sydney Heads.
He's fitted with a satellite tracker to help measure the success of his rehabilitation and provide data on the green turtle's preferred habitat.
Taronga Wildlife Hospital receives about 40 marine turtles for treatment each year.
They are tracking 13 turtles that have been successfully rehabilitated and released.
Australia is home to six of the world's seven marine turtle species, which help keep the ocean's environment in balance by keeping algae and sponge levels down, fertilising dune habitats and controlling jellyfish numbers.