Biofouling is a serious problem for any wetted structure, having a negative influence on applications as diverse as marine transport, implanted medical devices and water treatment. Here, we address this issue by creating a polydopamine-based coating on desalination reverse osmosis membranes incorporating a bromo-macroinitiator for subsequent polymerisation of sulfobetaine monomers into anti-biofouling polymer brushes. Surface characterisation using attenuated total reflectance-Fourier transform infrared spectroscopy and the water contact angle demonstrated the attachment of the polysulfobetaine brushes and that the hydrophilicity increased for the coated membranes. Using a macroinitiator formation time of ten minutes followed by polyzwitterion coating of one hour resulted in a 17% increase in water flux without significant effect on the salt rejection performance. These membranes also exhibited substantial suppression of protein and bacterial attachment of 69% and 88% respectively compared to unmodified membranes.