A portable pet canteen having a flexible bladder with peripheral edges and defining a footprint, an upper wall of the bladder defining an upper mouth, and a cavity being formed within the bladder. A rigid inner scaffold is secured to the upper mouth of the bladder and extends into the cavity. The inner scaffold has a height defined by side walls, the side walls having apertures for passage of water. An upper lid secures to an upper edge of the rigid inner scaffold such as with mating threads to form a closure such that the portable pet canteen is watertight. Water may be retained within the bladder until such time as the upper lid is removed and the canteen placed on the ground for the pet to drink from within the inner scaffold which provides a relatively wide opening. The canteen may be placed within a flexible outer cover for protection, which can also have various handles or straps for ease of transportation.