An absorbent prefastened product in the form of a disposable pants diaper is provided with a side closure arrangement on each side. The side closure includes front and rear side flaps having elastic portions where an inner surface (19, 19) of a rear side flap (8, 12, 9, 13) is overlapped and welded to an outer surface (18, 18) of a front side flap (6, 7). Each side flap (8, 12, 9, 13) is also provided with one part of a releasable fastening system (10, 11, 15, 16) located such that the weld is located on at least one of the elastic portions and such that it lies inward of the releasable fastening system in the prefastened state. A method of forming the absorbent product is also provided, in which an overlapped attachment is formed by joining front and rear side flap members (7a, 9a, 13a) together and attaching the side flap members (7a, 9a, 13a) to an absorbent chassis member.
