Otago Peninsula Trust marketing manager Sophie Barker said it was actually a "rare New Zealand sea lion" Sheeran spotted, "which was actually pretty amazing".
Sea lions stick to the sand while seals prefer rocks, she said.
Barker said staff came in on their day off to show Sheeran some of the wonders of the peninsula.
"We were just showing him the albatross, he got to help feed a little blue penguin," she said.
"Dunedin is the wildlife capital of New Zealand . . . it was pretty cool to be able to get him out on the peninsula and share that with him."
As well as the sea lion, penguins, and "four beautiful fluffy bundles" of albatross chicks Sheeran was able to see, there are 20 different species of bird on the peninsula.
"We offer something pretty special."
Barker said it was "exciting" that Sheeran chose to visit the Otago Peninsula.
"He brings joy to so many, hundreds of thousands of people, and it was nice for us just to be able to share something special about our area with him . . . that's why we went in on our day off, to try and do something nice."
Staff weren't allowed to take photos of Sheeran during the tour, but he used their cameras to take selfies with them, which the centre posted online.
Kia Ora fans
Yesterday we were fortunate enough to be able to share our beautiful birds - Albatross and Penguins with Ed...
Posted by The Royal Albatross Centre on Friday, 30 March 2018
"Thank you to all of our wonderful team and supporters who made the visit possible and respected Ed's privacy and kept the secret," they wrote on Facebook.
"We are so lucky to work in this amazing part of the world and to share and inspire people with caring about our fauna. Go forth and conquer plastic use, rampant consumption, care about our oceans and look after our wildlife - it's all of our future."
