A hydraulic connection apparatus for use by divers or an underwater vehicle is disclosed which allows pressurized hydraulic fluid to be supplied to hydraulically-actuated devices carried upon subsea equipment. A pressurized fluid source carried by the underwater vehicle is placed in fluid communication with the hydraulically-actuated devices by the connection apparatus. The connection apparatus comprises a buoyant device that is allowed to float upwardly into a receptacle carried by a portion of the subsea equipment. Co-operating hydraulic connection elements carried by the buoyant device and the receptacle provide a pressure tight seal between the device and the receptacle. Pressurized hydraulic fluid then flows from the buoyant device and through the receptacle to the hydraulically-actuated devices carried upon the subsea equipment.