Dewgong debuted in A Test in Paradise!, where Goh caught it while he and Ash were on their way to Dragonite Island. Though it was a hard Pokémon to catch, costing Go all of his Poké Balls, Goh finally caught Dewgong and officially added it to his team. Goh and Ash then rode across the sea on Dewgong, but during their journey, Dewgong spotted another Dewgong, fell in love with it, and chased after it, ignoring Goh's requests to stop. This led the group into a storm, which separated Dewgong from its Trainer.
Later, after being unable to find the other Dewgong, Goh's Dewgong reunited with its Trainer just as he and Ash were about to leave Dragonite Island to follow a group of Dragonite that had just left. Dewgong gave Goh and Ash a lift to the Dragonite, just in time to see one of them being captured by Team Rocket.
In A Snow Day for Searching!, Goh sent Dewgong out to explore a lake where a group of Mankey had dropped a Cubone's bone in. It used its Ice type as a barrier against the cold water while exploring the lake. Eventually, Dewgong found the bone and retrieved it.
In Panic in the Park!, Dewgong is one of the Pokémon affected by the disappearance of food at the Institute, when the group led by Goh's Scyther and Darmanitan clashes, Dewgong takes the lead using an Ice Beam and Water-type Pokémon group join the fight. When Golurk gets out of control, Dewgong helps the other Pokémon so that the three Cascoon of Goh can evolve safely.
In JN046, after being attacked by a Gyarados while looking for Mew, Goh used Dewgong to save himself. Despite this, they encountered a waterfall ahead and fell from it, forcing Goh to recall Dewgong.
