Four different polymer composites were made out of polyester resin, epoxy resin, glass fibers and flax fibers. Composites were produced by vacuum infusion and subjected to examinations of flexural and interlaminar properties in accordance with HRN EN ISO 14125 : 1998 and HRN EN ISO 14130 : 1997 standards. Examinations have determined the values of apparent interlaminar shear strength, flexural modulus of elasticity, flexural strength, deformation at break and mass fraction of fibers. The obtained results were compared with the requirements of the Croatian Register of Shipping (CRS) for glass fibers reinforced composites which are usually used in small shipbuilding. The results showed that the polyester resin / glass fibers composite has accomplished the best results and satisfied all the properties. On the other hand, the remaining tested composites have satisfied only one mechanical property and that was the flexural modulus of elasticity, whereas the other properties were not achieved. Epoxy resin / flax fibers composite and polyester resin / flax and glass fibers hybrid composite had the results closest to the prescribed one, whilst the polyester resin / flax fibers composite has achieved the worst results. The analysis concluded that biodegradable fibers reinforced composites have the potential to become a high-quality substitute for glass fibers reinforced composites, but further research, which will improve the production of biocomposites and connection between the matrix and the reinforcement, is needed.