The male common seal was found by a motorist on Nov. 28 at the beginning of December at the village of Capernwray, near Carnforth in northwest England.
Officials from the Royal Society for the Prevention of Cruelty to Animals, the RSPCA, took the pup to a wildlife center at nearby Nantwich.
The RSPCA said the seal, originally called Sid but renamed Ghost because of his hauntingly beautiful black eyes, was released back into the sea off northwest England on Saturday.
"It was a fantastic sight to see the seal released back in his natural habitat," said RSPCA officer John Littlewood, reports AP.
"He was found a few miles (kilometers) up the coast in Lancashire, but we released him back here because there is a healthy colony of gray and common seals."
"We wanted to get him back into the wild as soon as possible as he was healthy and showing a great appetite for herring. It was important that he didn't become too tame."
"Hopefully, he will thrive in the wild now and will not wander back onto land."
Between 1995 and 2002, the RSPCA released 134 common seals back into the wild, and the group says research shows their survival rate is good.
Nobody knows why Ghost was found so far inland, but the RSPCA says it was likely that he swam up a river and then waddled into the countryside.