Abstract: A demountable coupling device for submarine pipeline sections (33,34,35) where one or a plurality of conduits can be connected together on the seabed by a remotely controlled operation without the use of divers or guidewires. The connection of the pipeline sections, which are provided with square flanges (2), takes place by a vertical movement of the coupling unit (1) of the coupling device, which is provided with a groove (1') at each of its ends, the grooves being adapted for reception of the largely vertical portions of the pipeline flanges (2) when in an operating position on the seabed. The casing (1) of the coupling unit contains all components which are necessary for the connections.