<p>Natural fiber composites have been found to be durable and economical substitutes for synthetic composites in structural and industrial applications. The current work explores the mechanical behavior of coconut coir and hybrid coconut–banana fiber-reinforced composites in an epoxy resin matrix. Coconut coir and banana fibers, chosen for ease of availability and high strength-to-weight ratio, were treated with a 5% solution of NaOH for alkali treatment to improve surface roughness and interfacial bonding with the epoxy matrix. Specimens were hand lay-up molded following ASTM standards for tensile, impact, flexural, and hardness testing. The ratio of coconut to banana fiber in the hybrid composite was set at 80:20 for best reinforcement of the polymer matrix. Tensile testing showed the hybrid coconut–banana composite to have a higher tensile strength than the single coconut fiber composite due to the superior cellulose content and stiffness of banana fibers. Impact strength results were found to prove superior energy absorption capacity in hybrid composites due to the enhanced toughness by synergistic effect between the two fibers. Flexural analysis showed higher flexural module and stress-carrying capacity in hybrid samples, which is of primary relevance in load-bearing applications. Hardness testing following the Shore D method showed higher surface resistance in hybrid composites, proving superior interlocking of fibers and matrix and lower porosity. The work also included ANSYS finite element simulations to explore stress, strain, and deformation under tensile loading conditions. Simulation results were found to be comparable with experimental data, proving the enhanced performance of hybrid composites. Cost analysis indicated that hybrid composites are cost-effective, with raw material and fabrication cost far less than that of traditional synthetic fiber composites. Overall, this research is indicative of the potential of coconut and banana fibers as green reinforcements for polymer composites. By blending both fibers together, the resulting hybrid material produced exhibits improved mechanical performance, which makes it applicable in the automotive, building, and packaging industries. The results also show the significance of alkali treatment in maximizing fiber-matrix adhesion and load transfer efficiency. This research is indicative of the continued endeavor to substitute synthetic materials with renewable and bio-degradable materials without sacrificing performance.</p>