The demand for new materials and technologies that are able to minimize the environmental impact generated by the disposal of materials from fossil sources has increased significantly in the past years. As these materials normally include gelatin, a high cost ingredient, our aim was to find a more effective solution through the development of films based on protein isolate sourced from Nile tilapias. Thickness, water solubility, water vapor permeability (WVP), tensile strength, elongation, color attributes, and opacity were evaluated. Casting technique was used to obtain the films, using different combinations of protein isolate, gelatin, and plasticizers (glycerol or sorbitol) in an experimental design 2 3. The films showed good continuity and handling. Surface was free from bubbles and cracks. Key results observed: thickness from 0.04 to 0.09 mm, solubility in water from 4.11 to 28.72%, WVP from 7.12 to 16.36 g mm d −1 KPa −1 m −2 , tensile strength from 12.43 to 155.57 MPa, and elongation from 2.14 to 125.33%. Gelatin protein films were promising from the point of view of mechanical properties, visual appearance and easy handling, as well as low WVP and low solubility in water. However, the replacement of gelatin in the formulations implicated in films with reduced tensile strengths.