The invention relates to a method for producing a container from thermoplastic material having a connection element (5) passing through the wall thereof. The method comprises making available at least one plate-shaped or shell-shaped or tube-shaped preform (3) made of plasticized thermoplastic material, introducing the preform (3) into a multipart molding tool (1) having cavities defining at least one molding recess, molding and final shaping of the preform (3) within the molding tool (1) using differential pressure, piercing of the still warm-plastic preform (3) from the tool side by means of a mandrel (9) in order to produce an opening (6) in the preform (3), insertion from the molding recess side of a connection element (5) into the opening (6) produced by the mandrel (9), and connection of the connection element (5) to the preform (3).