The self-healing effect and durability of hydrogels formed as a thin coating on a substrate were investigated in order to protect the surface of a mechanical component that experience contact sliding. Particularly, the physical, mechanical and tribological properties of hydrogel coatings were assessed. The morphology of hydrogel coatings greatly changed according to the formation conditions of the coating. Accordingly, the mechanical and tribological proper-ties of hydrogel coatings varied significantly. Compared with a completely dried hydrogel coating formed by a freeze-drying process, the durability and tribological properties of the hydrated hydrogel coating formed by contacting with water were greatly improved. Moreover, the wear track formed on the surface of the hydrogel coating after reciprocating sliding in a state of contact with a ball tip at a constant load was self-healed by contacting with water. The main mechanism of the self-healing effect of the hydrogel coating was postulated to be due to the swelling behavior of hydrogel fibers and the osmotic phenomena of water molecules. The results of this study will contribute to the development of self-healing coatings for surface protection in precision components and biomaterials.