Nanostructuring of metal oxides is a straightforward strategy for enhancing photoelectrochemical (PEC) performance. The present work demonstrates the anodization of W metal to determine the optimum WO₃ nanostructure for use in photoanodes. Anodization was performed in a fluoride-containing 1 M Na₂SO₄ electrolyte. Under optimum conditions, WO₃ nanocoral structures were fabricated. The forming mechanism of the nanocoral structures was elucidated by the generation and development of nanobubbles at the metal/oxide interface. To enhance the PEC performance, BiVO₄ layers were coated on the anodic WO₃ nanocoral structures and annealed at 500 °C in air atmosphere. The prepared BiVO₄/WO₃ nanocoral layers were characterized by SEM, XRD, EIS and UV–vis spectroscopy. They were then used as photoanodes for PEC and IPCE measurements. Consequently, photocurrent density was improved to 0.42 mA/cm² at 1.23 V vs. RHE and IPCE at 400 nm (21%) was enhanced by 21 times due to the producing band alignment between BiVO₄ and WO₃.