Abstract: A method and an arrangement are described for underwater arc welding in which the welding electrode is placed into the zone to be welded in lying position, the electrode being covered with a shield structure and ignited so that, when electrode burning occurs, it produces the desired weld at the zone to be welded. A mantle is used as the shield structure and comprises an inner burning layer made of a readily burning, preferably resilient material, by means of which the electrode is covered, and an outer protective layer, preferably made of a flexible material, by means of which the burning layer is covered, and fastening means, by which the mantle is fixed firmly and tightly in position. The fire gases produced during the burning of the electrode and of the burning layer prevent penetration of water to the electrode.