The method and the device serve for the blow moulding of containers (2). Preforms (1) of a thermoplastic material are heated in the region of a heating path (24) and then transferred to a blowing device (25). The blowing device (25) is provided with at least one blowing station (3) for moulding the preforms (1) into the containers. The preforms (1) are retained along at least a section of the transport path thereof by a support element (46) which is at least partly loosely introduced into a mouth section (21) of the preform (1) and tightened in the mouth section (21) after the introduction thereof.