A flexible, polymer, composite tube (1) adapted for transport of fluids such as hydrocarbons, e.g. oil and/or gas, and flexible enough to be coiled with a curvature radius as short as approximately 20 times its outer diameter. The flexible riser (1) comprises the following structural elements: an inner liner (2) of thermoplastic material, an intermediate reinforced, polymer, multi layer component (3), and an outer thermoplastic liner (4). The inner liner (2) is continuously bonded to the intermediate, multi layer component (3), which again is continuously bonded to the outer liner (4). A method for manufacturing the flexible tube (1) by welding or gluing is also described.