In this study, we adapted a straightforward approach for fabricating a novel ternary heterojunction of Au/BiVO4/WO3 photoanode. The electrochromic properties of WO3, when capped with BiVO4, were harnessed to facilitate the localized reduction of Au nanoparticles (NPs) preferentially at the tips of the WO3 nanobricks. We systematically varied the number of consecutive drop-casting applications to optimize the amount of BiVO4 on FTO conductive glass and WO3, while maintaining a constant thickness for WO3. This optimization aimed to establish a correlation between the morphological and crystallinity features and the enhanced PEC water splitting performance of BiVO4/WO3 photoanode. Notably, the optimal photocurrent obtained from the BiVO4-2c/WO3 (BiVO4/WO3 heterostructure with 2 layers of BiVO4) configuration further increased upon the decoration with plasmonic Au NPs. This study provides insights into the role of plasmonic metals in improving the efficiency of semiconductor-based heterojunctions and offers a novel approach for optimizing the design of advanced PEC systems.