In this current study, five types of strong, stiff, and lightweight composites were developed utilizing hand lay-up and cold press methods by the hybridization of JUCO and carbon fabrics. Before the fabrication of the composites, the surfaces of the JUCO fabrics were treated with a 5% NaOH aqueous solution. To evaluate and compare the mechanical characteristics of the fabricated composites, tensile, flexural, impact, and hardness tests were conducted. Specimens were also aged in artificial seawater (pH 8) for 150 days to explore the effects of seawater aging on the mechanical characteristics of the composites. Numerical analysis of the tensile and flexural properties was also done by the finite element method (FEM). The findings from the current study showed that hybridization with carbon fibers considerably enhanced the mechanical properties of the natural fiber-reinforced composites. On the other hand, a decrement in tensile strength, flexural strength, and hardness, and an improvement in impact strength were noticed due to fiber degradation as a result of aging in seawater. Results obtained from the numerical analysis also displayed good alignment with the experimental findings.