Compared with traditional electrolytic technology, directly using photocatalytic materials to produce hypochlorous acid from chlorine‐containing water undoubtedly has stronger low‐carbon and environmentally‐friendly characteristics. However, currently reported materials with photocatalytic chlorine production performance require precious metal Pt for catalysis, which undoubtedly greatly increases production costs. Therefore, developing new types of non‐precious metal‐based photocatalytic materials for efficient hypochlorous acid synthesis has significant implications. In this study, we demonstrate a novel breakthrough by showing that the WO3/CdS with a Z‐scheme structure effectively generated 3.54 mg/L of free chlorine in a 0.5 M NaCl solution, while also exhibiting spectral bactericidal and algal inhibition properties. The Z‐scheme structure can effectively prevent carrier recombination and improve photocatalytic efficiency. Therefore, this research provides a novel approach to photocatalytic antifouling and holds significant implications for the application of photocatalytic technology in the marine antifouling industry.