Abstract: A locking swivel device is provided for connection with a proximal end of a drill string and for conducting a drilling fluid to the drill string. The device is comprised of a housing and a mandrel rotatably supported within the housing such that an annular space is defined between the housing and the mandrel, wherein one of the housing and the mandrel is connectable with the drill string such that the drill string rotates therewith. A clutch assembly is positioned within the annular space which is actuatable between an engaged condition in which the clutch assembly engages the housing and the mandrel in order to inhibit the rotation of the mandrel relative to the housing and a disengaged condition in which the clutch assembly disengages the housing and the mandrel in order to permit the rotation of the mandrel relative to the housing. The clutch assembly is actuated to the engaged condition by a pressure exerted by the drilling fluid.