The invention relates to an improved watercraft cover, as well as its method of use. In some embodiments, the watercraft cover's support structure is normally irreversibly integrated into or retained by a sheet of the watercraft cover, and the support structure and the sheet are collapsible together for portability without separating the support structure and sheet. The invention also provides for improved retention systems useful for retaining the watercraft cover on the watercraft. Watercraft covers in accordance with the present invention are particularly useful for providing improved portability while preventing water collection.