The invention relates to a process for the friction stir welding of two panels (20, 21), using a welding device (25) having a retractable pin (29), comprising the following steps: positioning the two panels (20, 21) so as to be in contact over an overlap region (24) and keeping them in the desired relative position after welding; bringing the welding device into contact with the upper panel at the start of the welded joint; longitudinally welding the two panels, by moving the welding device as far as the end of the welded joint; continuing to move the welding device (25) along a path extending beyond the end of the welded joint; and retracting the retractable pin (29) so as to prevent the appearance of a weld hole in a portion of the path of the welding device (25) extending beyond the end of the welded joint.