The grey seals, named Scribbly Gum and Echinacea, were found underweight and suffering from injuries earlier this year.
Scribbly Gum, who was rescued in January from sea water in Waterford, was found with a swollen eye which left him struggling to hunt for food.
Sam Brittain, who works as a animal care manager at Seal Rescue Ireland, said he was just a couple of months old when they took him in.
“His eye was very swollen and we tried a few different medications to get the swelling down, however, it didn’t work and it was much bigger and more protruding than his other eye,” Sam said.
“So he had to have surgery to remove his eye in May so that it didn’t give him any issues when he went back to the wild.
“He was wonderful after and went up to a lovely weight of 50 kilos from 20 kilos when he came in.
“He got released today and it was very successful.”
Echinacea, who was rescued in April from Donegal, was underweight and suffering from baldness.
“He also had this other issue and we determined that it was probably due to a parasitic infection that he had,” Sam added.
“He put on all the weight he needed to be a healthy seal.
“The main thing is that they get to a good weight and can eat fish by themselves and that they’re competing really well against each other for the fish, so once they get out in to the wild they know they have to eat fast or someone else will eat ahead of them.
“These two boys were fine and healthy and it went really well. Echinacea took off into the water straight away like lightning bolt.
“But Scribbly Gum was a little bit more hesitant in the cold waters. But eventually he went out deep and that’s fine.
“I would expect it will take them a couple of days to get used to the wild again but they will be fine.”