Electrochemical systems are often limited by the mass transport of reactants to the electrode and products away from the electrode. Here, we demonstrate that strategically fouled electrodes generate electrochemically induced density gradients that drive natural convection, enhancing mass transport under otherwise quiescent conditions. Using electrochemiluminescence (ECL) microscopy, we directly visualise the local enhancement of electrochemical activity around conductor–insulator boundaries and investigate how electrode geometry, electrolyte composition, and orientation relative to gravity influence convection-driven transport. Strategic electrode fouling induces flow velocities of up to 0.4 cm s⁻¹, resulting in local reaction rate enhancements of up to 290%, while micrometre-scale insulating arrays produce a net increase in electrolysis rates despite reducing the electroactive area. The magnitude of the enhancement depends strongly on electrode orientation and the physicochemical properties of the electrolyte, highlighting density-gradient-driven convection as a simple yet powerful mechanism for overcoming mass-transport limitations. These findings establish controlled electrode heterogeneity as a new design strategy for enhancing electrochemical processes and demonstrate its potential for applications in electrosynthesis and electrochemically coupled enzymatic reactions.