Water repellency has significant potential in applications like self-cleaning coatings, anti-staining textiles, and electronics. This study introduces a novel nanocomposite system incorporating functionalized Al₂O₃ and CeO₂ nanoparticles within a polyurethane matrix to achieve hydrophobic and UV-blocking properties. The nanoparticles were functionalized using an octadecyl phosphonic acid solution and characterized by FTIR and XPS, confirming non-covalent functionalization. Spin-coated polyurethane coatings with functionalized and non-functionalized Al₂O₃, CeO_2, and binary Al₂O₃-CeO₂ nanoparticles were analyzed. The three-layered Al₂O₃-CeO₂-ODPA binary system achieved a contact angle of 166.4° and 85% transmittance in the visible range. Incorporating this binary functionalized system into a 0.4% w/v polyurethane solution resulted in a nanocomposite with 75% visible transmittance, 60% at 365 nm UV, and a 147.7° contact angle after three layers. These findings suggest that ODPA-functionalized nanoparticles, when combined with a polymer matrix, offer a promising approach to developing advanced hydrophobic and UV-protective coatings with potential applications across various industrial sectors.