Abstract: A device is provided for closing off an interior portion of a pool skimmer when the pool is to be shut down for a prolonged period of time. The device includes an inflatable member of pliable, expansible, water-proof material. When the member is inflated, subsequent to being positioned within an interior portion of the skimmer, the member will close off a surface skimming inlet of the skimmer. The inflatable member is provided with a valve for controlling the inflating and deflating of the member. When the inflatable member is disposed within the skimmer interior portion, the valve is accessible through an access opening formed in the skimmer.