Understanding mass transport mechanisms in VRFB electrodes is critical to improving performance, efficiency, and depth-of-discharge. In this study, diffusion and convection are experimentally investigated in a VRFB test bed using a strip cell architecture, having only one straight channel and 1 cm2 active area. To study diffusion and convection-dominated mass transport regimes, various channel depths (0.25, 0.5, 1, 2.5 mm) are employed. The diffusion-dominated condition is imposed with deeper channel depths while convection-dominated condition is achieved with shallower channel depths. It is found that diffusion-dominated cells have large current gradients; convection-dominated cells have relatively uniform current distribution from inlet to outlet under a mass transport limited condition. Although increasing flow rate is frequently found to improve electrochemical performance, it is observed that there is no discernible change in current distribution when increasing flow rate in diffusion-dominated VRFB cells. Pressure drop tests also show that superior electrochemical performance can be achieved with reduced relative pressure drop in convection-dominated cells. In light of such findings, an optimization point is proposed for the strip cell architecture; such a point will vary with any other architecture and system, but this approach can be applied to any flowing system.