Abstract: A fly opening includes two overlapping fabric panels, a two-part magnetic closure, and a mechanical catch. The two overlapping fabric panels define an elongate aperture in the garment between the panels. A two-part magnetic closure includes a first magnetic part attached to one of the panels within the overlap region, and a second magnetically-responsive part attached to the other the panel. The first and second magnetic parts are positioned such that when the parts are magnetically connected, the panels are held together in face-to-face abutment. The mechanical catch includes cooperating catch portions located on each of the panels, and arranged to resist or prevent relative movement of the fabric portions in a direction parallel to their plane of abutment and perpendicular to the elongate aperture.