The loggerhead turtle was affected by the cold, had shell damage and had signs of an infection.
It was found on the stretch of beach between the Dicq shack and Rice bowl and was taken to the nearby New Era Veterinary Hospital for treatment.
After an appeal it is being moved to a special tank at the fresh fish company at La Collette.
A number of turtles have washed up in the UK in recent months, but most have been too ill to save.
Vets have been treating it with antibiotics and fluids and say the turtle has a "poor prognosis".
They will use the tank to slowly raise its temperature.
A turtle which was found on a beach in St Clement is being treated at a veterinary hospital in Jersey.