An insert for protecting the breathing airway of an infant conforms to the incline angle of an infant seat, such as a car seat, high chair, stroller, or jogger. Preferably the insert is hinged so it can be used in an infant seat or laid flat for use on a changing table or other flat surface. In use, two side rolls contact the infant to prevent it from moving sideways. A bottom roll prevents slouching in the seat and supports the infant's legs when laid flat. Preferably, the bottom roll is removable so the insert may be used with larger infants who do not need the provided support. An adjustable shoulder roll extends between the side rolls and can be moved up or down for proper placement behind the infant's shoulders. The shoulder roll compensates for the infant's rearward-elongated head, keeping it in a natural position to avoid compromising the airway. The rolls are preferably made of memory foam and covered by machine-washable fabric.