A quick connect/disconnect coupling assembly particularly adapted for underwater use, having a pair of coupling members, one of which is mounted on a relatively rigid structure, and a sleeve mounted over the first coupling member for relative axial and rotational movement. The sleeve is guided by a single or double J slot between axially extended locking and axially retracted unlocking positions. In the locking position, a cammed surface on the inside of the sleeve engages a ball and socket arrangement on the coupling members to prevent the coupling members from becoming unlocked; in the axially retracted unlocking position, the cammed surface of the sleeve is moved away from the ball and socket arrangement to permit free radial movement of the ball out of the socket and relative axial movement of the coupling members into and out of coupling engagement with each other. The sleeve is lockable in the axially extended locking position to provide a positive lock. Locking and unlocking is accomplished by specific pulling, twisting and pushing forces on the sleeve and/or coupling members.