A method for connecting coupling parts of a subsea coupling arrangement, the coupling parts having at least one sealing surface, in which the coupling parts are connected by displacing the coupling parts towards each other, wherein a watertight seal is formed when the coupling parts are connected, feeding filtered sea water through a channel into a space between the coupling parts during the displacement, flowing the filtered sea water over the sealing surfaces to prevent particles and dirt from being trapped between the sealing surfaces, and discharging the filtered sea water from the space into surroundings of the subsea coupling arrangement.