Swablu is an avian Pokémon with a round, blue body. Since it has no discernible neck, its body appears to be all head. There are two long feathers on top of its head, and it has a short, rounded white beak and beady, black eyes. Its wings are fluffy and white, resembling cotton or clouds. It has tiny, white feet and two pointed tail feathers.
Swablu does not like dirty surroundings, so it cleans things with its cottony wings. It uses streams and freshwater springs to wash its wings when they become dirty from polishing. It is commonly found living in flocks in forested habitats, but often flies closer to towns during the spring. Swablu is very friendly and largely unafraid of humans. As a result, it frequently perches on people's heads like a fluffy hat.