The invention relates to a plastic closure (1) for containers (10), comprising an accommodating region for accommodating an opening section (10a) of the plastic container and comprising a puncturing region (2) that is suitable and intended for being pierced and penetrated by a piercing device in a specified piercing direction (L), wherein said puncturing region (2) is arranged on a lid surface (1a) of the plastic closure. According to the invention, the plastic closure (1) has a reinforcing device (20) which is arranged at an offset from the puncturing region (2) in the piercing direction and which is suitable for increasing the force acting opposite the piercing direction during the piercing process due to the puncturing region (2), wherein the plastic closure (1) is preferably designed as a one-piece plastic closure.