A watertight equipment cover for outdoor or marine use that includes an interior and exterior surface, with the interior surface configured to fit substantially adjacent to and to completely enclose a piece of equipment such as photographic equipment or portable electronic equipment. The cover includes transparent portions that allow, as required for operation, either the equipment to transmit or receive light, or the operator to view specific areas of the equipment while the equipment is enclosed in the cover. The cover further includes resiliently deformable portions that enable operation of the equipment control functions while the equipment is enclosed in the cover. The cover further includes a watertight sealing mechanism that is sealable and resealable by the end user. An outdoor or marine protective cover system that includes a watertight cover and a piece of equipment.