A water balloon cannon including a barrel with a bore diameter designed to receive a water balloon. The barrel extends between a muzzle and a rear portion, where the rear portion defines a compressed air port and a water port. The water balloon cannon further includes a water valve for introducing a volume of water through the water port into the rear portion of the bore diameter, and an air valve for introducing a flow of compressed air through the compressed air port into the rear portion of the bore diameter. The volume of water is designed to act as a buffer between the flow of compressed air and the water balloon positioned within the bore diameter.