Phenylphosphonic acid (H2PP) is investigated as a corrosion inhibitor of hot dip galvanized steel (HDG) fully immersed in a 5% (w/v) sodium chloride electrolyte. An in-situ Scanning Vibrating Electrode Technique (SVET) is used where concentrations of H2PP are systematically added to the electrolyte in neutral conditions. H2PP, at a concentration of 5 x 10(-2) mol dm(-3), is shown to effectively inhibit localized corrosion over a 24 h period with 96% efficiency. H2PP is compared with a sodium phosphate (Na3PO4) inhibitor at the same concentration over a wide pH range. (C) The Author(s) 2017. Published by ECS. All rights reserved.