Barnacle Bill, who washed up on Chouet after Storm Ciaran, has put on nearly one pound in weight and is ready to travel.
The GSPCA will fly the small female loggerhead turtle back to Gran Canaria in a private jet in the New Year.
Barnacle Bill will be joined on the journey by a shelter staff member to ensure she arrives safely.
Charity manager Steve Byrne says her recovery has been amazing:
"We've been feeding Barnacle Bill a mixture of squid which our last turtle really enjoyed and also bits of fish.
She's been eating really really well, for such a small turtle to put on 400 grams in such a short period of time is just incredible and we are really pleased."
A chip has been put in the creature's front left shoulder so Barnacle Bill can be identified in the future.
She was named after the shellfish attached to her which were removed by a local vet shortly after being taken to the GSPCA but it's understood despite the name, she is female.
Steve Byrne says adjusting after the flight may take her some time.
Civil servants delay briefing politicians in Guernsey over hospital's escalating costs
Eco travel in Guernsey: swimming to work
Guernsey doctors will stop prescribing pain relief plasters
Candidates in Guernsey's 2025 election may not get a campaign grant