The multi-layer tape wrapped tubing for effectively impeding the diffusion of vapor is made in a continuous in-line process and has three distinct layers: an inner tubing layer, a middle diffusion barrier layer and an outer jacketing layer. The inner tubing layer comes into contact with liquid and vapor. Vapor that might ordinarily diffuse through the tubing is impeded by the diffusion barrier layer. The diffusion barrier layer is a laminate comprising a diffusion barrier film with a very low vapor diffusion rate sandwiched between layers of thermoplastic. The diffusion barrier layer is wrapped around the inner tubing one or more times. The outer jacket layer is a polymeric jacket which is extruded onto the diffusion barrier layer wrapped inner tubing.