Superhydrophobic (SH) coatings have garnered significant attention due to their excellent water repellency, self-cleaning behavior, and anti-icing potential. However, the practical implementation of SH coatings is often limited by their poor mechanical durability, as the micro/nanostructures essential for water repellency are vulnerable to abrasion and impact. In this study, we present a mechanically durable SH coating enabled by strong interfacial bonding between an epoxy matrix and silica nanoparticles functionalized with hydroxyl-terminated polydimethylsiloxane (H-PDMS). The resulting siloxane-functionalized silica nanoparticles form a robust hierarchical structure, achieving a high water contact angle of 167° and a low sliding angle of 2°. Covalent bonding between the epoxy resin and the modified silica substantially enhanced the coating’s mechanical integrity, maintaining its superhydrophobicity after 100 abrasion cycles and 5 min of continuous sand impact. Moreover, the coating exhibited low ice adhesion strength (53.1 kPa) even after mechanical wear, demonstrating its potential for icephobic applications. This work provides a robust interfacial design strategy for developing mechanically durable and icephobic SH coatings suitable for harsh environmental applications.