Tiller was just days old when he was spotted in distress at North Queensferry, by men working on the new Forth crossing.
After three months in the care of Scottish SPCA he has been returned to the water at Silver Sands, Aberdour where there are seal colonies nearby.
Colin Liddell, from National Wildlife Rescue Centre near Alloa, said: "Tiller was our first grey seal pup rescue of the season, and he's now one of the first to be released back into the water after a very successful period of rehabilitation.
"He was accompanied by another male pup, named Ferry, who came into us at the beginning of November from Uist.
"We're confident both boys will join the local colonies and help maintain the grey seal population on the east coast of Scotland and around the Forth Estuary."
The Scottish SPCA said it has rescued 53 grey seal pups so far this winter, about 40% more than were rescued by the same time last year.