Abstract: The present invention is concerned with a cryostat joint assembly for use in joining superconducting cables, in particular for simplifying the connection between the cables while ensuring a robust electrical and mechanical connection, the joint assembly including first and second endcaps each terminating one of the cables, each end cap including an electrically conductive tubular plug, and a coupling connectable between the first and second end caps and defining first and second tubular sockets for receiving the first and second plugs such as to provide a cryogen conduit extending through and defined by the pair of plugs and sockets to simultaneously enable the flow of cryogen and electrical current through the joint assembly.