AbstractA new method for rapid late‐stage fluorination using the cation pool technique is presented. Fluorination and no‐carrier‐added radiofluorination of methyl (phenylthio) acetate, methyl 2‐(methylthio) acetate, and methyl 2‐(ethylthio) acetate were performed. The carbocations formed through electrochemical oxidation were stabilized by using a divided electrochemical cell and 2,2,2‐trifluoroethanol (TFE) as the solvent at −20 °C. At the end of electrolysis, either stable‐isotope [19F]fluoride or no‐carrier‐added radioactive [18F]fluoride was added to the reaction mixture to form the fluorinated or radiofluorinated product.