<p>Polymer composites reinforced with woven natural fiber fabric are commonly used in marine vehicles. This study investigated the impact of sea water degradation on the mechanical performance of these composites. The laminates were fabricated using various stacking sequences of jute (J) and aloe vera (A) woven fabric (A/A/A/A, A/J/J/J, J/A/J/J, J/J/A/J and J/J/J/J) with polyester resin. Specimens were cut from the laminates according to standard procedures and immersed in fresh and sea water at room temperature for 12&#xa0;days. The water absorption and strength qualities of the composites were examined daily. The free vibration behavior of the aged composites was also investigated. Compared to dry composite specimens, the JJAJ composite exhibited superior fiber matrix adhesion, resulting in enhanced water resistance and reduced permeability in both normal and saltwater environments. The dry composites exhibited superior bending capability compared to the polyester matrix. However, upon aging in normal and saltwater, their bending strength and modulus decreased by 13–56% and 12–16%, respectively. The natural frequency of the aged specimens reduced by 11–32% in normal water and 6–23% in saltwater in all the vibration modes. According to the morphological assessment, the primary failure modes of the aged composites were identified as peeling, cracking and bulging, which were caused by water diffusion. This study contributes to the development of environmentally benign, natural fiber-reinforced marine composites with increased durability and mechanical performance in hostile aquatic conditions.</p> Graphical Abstract <p></p>