Pipa pipa mates in a series of underwater somersaults. As the pair turns, the female releases eggs which the male fertilises and presses onto her back with his belly and hind feet. Over the following days her dorsal skin swells around each egg and forms a pocket, sealing it in a shallow chamber.
Development proceeds inside these pockets for roughly three to four months. The embryos draw on yolk rather than feeding, pass through the tadpole stage without ever swimming freely, and emerge as miniature toads a centimetre or two long, pushing through the skin one at a time. A single brood commonly numbers in the dozens. The female afterwards sheds the modified skin layer.
The adult is also unusual at the front end. It lacks a tongue, and it detects prey with sensitive star-shaped tips on its long fingers before gulping food in with a sudden expansion of the mouth. The species is one of the few frogs that never leaves water as an adult.