A protective cover device for a spa, adapted to fit over a spa and a spa's insulated cover. The device comprises a center panel that covers the top of the spa and side panels that cover the sides of the spa. Corner panels may be attached to the side panels to cover the corners of the spa. Coupling means on one side of each side panel of the device help to keep the device in position over the spa and the spa's insulated cover. The device may be adjustable so as to accommodate varying spa sizes. The device's exterior may be used for advertising by placing names, logos, or the like thereon.