Dive Otago and Experiencing Marine Reserves spokeswoman Amelia Saxby said 18 people, a mix of children and their parents, attended the trip.
The participants were taken to the island from Back Beach in Port Chalmers on a Dive Otago boat for the snorkelling trip.
``But once you got nice and close to the rocks you could see a lot of sea snails, algae and worms and crabs.''
First-time snorkeller Des Karl, of Dunedin, said he had ``an awesome time'' and would snorkel again.
Miss Saxby said Experiencing Marine Reserves would put on more snorkelling trips in different sports around Dunedin ``in an attempt to get people into the water - once it's warmed up a bit''.
Meanwhile, at the Wild Dunedin exhibition at the community gallery in Dunedin yesterday were Xavia Hurring (7) and Zev Burgess-Smith (9), both from Port Chalmers.