Local liquid-to-wall mass transfer enhancement by a single bubble was studied. Both photographic and local current measurements were taken. The effects of the bubble form, wake and trajectory were analysed for vertical and down-facing inclined electrodes. For angles lower than 40-degrees, bubbles rise over the surface with small hops of regular amplitude. High current increases were observed where the bubble hits the electrode. For higher angles, the bubble glides, producing high constant currents.