A method of manufacturing permanently curved electrochromic devices is presented. The method includes provision (210, 211) of two plane thermoplastic substrates at least partly coated by an electron conducting layer. The substrates are further at least partially coated (220, 221) with an electrochromic or a counter electrode layer. The coated substrates laminated (230) together with an adhesive electrolyte layer in the middle into an electrochromic laminate sheet. The electrochromic device is formed (240) by thermoforming the covered substrates into a permanent curvature, prior or after the further coating, prior to the laminating of the substrates or by thermoforming the electrochromic laminate sheet after the lamination. Once formed, the coated substrates or electrochromic device, respectively, permanently remains in its curved shape. Additional layer, such as bus bars and layers for chemically adaptation can be provided onto the substrates prior or after the thermoforming step.