After being stabilised by medics, Smores was taken to the sanctuary where the team began intensive treatment.
The sanctuary said the pup made a full recovery following weeks of expert care, nutrition and treatment.
She was “ready to begin life back in the ocean” after reaching a target weight of 30kg, said rescuers.
Senior animal care specialist and research coordinator Anne van Domburg said: “Watching Smores head back into the water is exactly why we do what we do.
“She came to us vulnerable and exhausted, and seeing her now strong, healthy, and ready to thrive in the wild is incredibly rewarding for the entire team.”
The sanctuary said it was currently caring for 12 seal pups.