A foldable shield transformable from an extended use position to a folded transport position and vice versa includes shield plates and spring loaded hinges connecting the shield plates. Restraint devices hold the shield to a user's forearm during use. A release device releases cooperating locks so that the hinge devices bring the shield plates from the transport position to the extended use position. The shield is brought to the transport position by folding of the first shield plate toward the second shield plate and folding of the third shield plate against the first shield plate. The first shield plate has a maximum width between the long sides that is less than corresponding widths of the other two shield plates for sufficient clearance for the folding of the third shield plate. When folded, the shield plates are located on top of each other in a substantially flat package.