Here, we present a range of datasets that have been compiled from across six countries in order to facilitate image velocimetry inter-comparison studies. These data have been independently produced for the primarily purposes of: (i) enhancing our understanding of open-channel flows in diverse flow regimes; and (ii) testing specific image velocimetry techniques. These datasets have been acquired across a range of hydro-geomorphic settings, using a diverse range of cameras, encoding software, controller units, and with river velocity measurements generated as a result of differing image pre-processing and image processing software.