Pit dissolution rate on samples of an AISI 304 stainless steel (SS) in natural sea water was assessed using a scanning reference electrode technique (SRET) and compared with chronoamperometric measurements. Corrosion pits generated in AISI 304 SS samples under potentiostatic control at room temperature and smooth surface presented an empirical exponential growth rate law. The quantity of dissolved metal per pit as a function of polarisation time determined using SRET and chronoamperometric measurements presented acceptable agreement. Considering the capabilities and limitations of scanning techniques, this study presents an approach of the pit growth rate determination from SRET measurements demonstrating the possibility to perform real time quantitative determination of localised dissolution rate.