The castle of La Vilavella (Castellón) stands on the slopes of San Sebastián, and its various constructions follow the craggy relief of the hill, on the outskirts of the town to the west. The castle is currently an imposing ruin on top of a hill, a landmark which dominates the inland landscape as well as the plains to the sea. Part of the castle’s walled complex, which stretches along 230 m of the local topography with a maximum width of 60 m, is conserved. The walled complex incorporates a sequence of towers of different types, forms, and constructive techniques which reflect the different periods in which the complex was built. This article aims to present the conservation project carried out in the castle, as well as the prior analyses and completed work based on these. The starting point for this conservation project was that the actions on a major heritage asset such as this constitute another phase for learning about its material history. They also make it possible to continue research into its material and constructive history through new archaeological excavations such as the study of its constructive elements. The interventions carried out aim to respect the construction of the castle at both a material and aesthetic level, returning it to a physical condition which honours its history and helps prolong its useful life. The conservation work carried out, necessary to ensure consolidation, has focused mostly on the walls of the different structures and adaptation and musealisation actions of the castle complex.