An infant nasal interface mask for use with a nasal continuous positive airway pressure (nCPAP) system including a mask body and a base. The mask body forms a cavity and is defined by a leading portion, an intermediate shell portion, and a trailing portion. The leading portion terminates in a leading edge forming an aperture open to the cavity and having a generally triangular shape for placement over a patient's nose. The trailing portion includes a bellows segment characterized by an increased flexibility as compared to a flexibility of the intermediate shell portion. The base extends from the trailing portion opposite the leading portion and forms at least one longitudinal passage extending through a thickness of the base and fluidly connected to the cavity. The intermediate shell portion is laterally pivotable relative to the base via the bellows segment.