In the present study, the influence of bed slope on the hydrodynamic performance of a floating oscillating water column (OWC) device is investigated. Numerical computations are performed using the incompressible multiphase volume of fluid (VOF) approach. A dynamic meshing technique is adapted to capture the body motions for different wave conditions. The flow phenomena as well as the free surface elevations are investigated for the OWC device considering a range of wave periods. The results of this study indicate that the hydrodynamic capture efficiency for the floating OWC device may be significantly higher with a sloping bed. However, the dependence on the slope is observed to vary with the time period of the incident wave. This study should be applicable to wave energy converter devices installed near shore, where the presence of sloping bed has an influence on the hydrodynamic behaviour and hence the capture efficiency.