Popplio is a pinniped Pokémon that is primarily blue. It has large eyes, a long, white snout with black whiskers, and round, pink nose. There is a small, rounded earflap on each side of its head. Around its neck is a light blue ruff, which extends past its shoulders. It has four flippers. The front flippers are larger than the hind, and have white markings separating its toes.
Popplio is able to snort bubbles of water from its nose, which it uses as part of its battle strategy, and it can swim at 25 mph (40 km/h). On land, it uses the elasticity of its bubbles to perform acrobatic stunts and jumps.