Abstract: To address the pronounced wave-induced motion responses of offshore floating photovoltaic (FPV) platforms and the strong environmental dependence of standalone photovoltaic power output, this study proposes an integrated FPV system incorporating oscillating water column (OWC) devices. In the proposed system, the OWC devices are symmetrically arranged around a pontoon-truss-type FPV platform, enabling additional wave energy capture while regulating the hydrodynamic response of the floating platform. Based on potential-flow theory and time-domain coupled analysis, a coupled hydrodynamic and energy-capture numerical model is established, in which platform motions, OWC water-column responses, equivalent power take-off (PTO) damping, and mooring constraints are considered. The motion responses and wave energy capture characteristics of the FPV-OWC integrated system under regular waves are investigated, and the effects of OWC chamber diameter and wave incidence angle on the overall system performance are further analyzed. The results show that the introduction of OWC devices has a limited influence on the overall heave response of the platform and does not significantly change the dominant heave restoring mechanism, but it can effectively suppress the platform surge and pitch responses in the low-frequency range. The wave energy capture of the integrated system is mainly concentrated in the high-frequency operating range. Owing to stronger local wave excitation, the up-wave OWC units generally exhibit higher energy capture capacity than the lee-side units. Within the investigated range, increasing the chamber diameter enhances the suppression of platform surge response in the medium- and low-frequency ranges and improves the wave energy capture performance within the high-frequency operating range. However, it does not significantly broaden the effective energy-capture bandwidth, indicating that a larger chamber diameter mainly increases the energy conversion intensity within the primary operating band. Under oblique wave conditions, the integrated system exhibits better energy capture performance. As the wave incidence angle increases from 0° to 45°, the platform surge and pitch responses decrease, while the total mean power of the OWC array within the primary operating band increases. The superior overall performance in the 45° wave-incidence case is mainly attributed to the enhanced combined power contribution of multiple OWC units. Overall, integrating OWC devices with offshore FPV platforms can improve certain motion responses while enabling additional wave energy utilization, providing a reference for the structural design and parameter optimization of offshore FPV-based multi-energy complementary systems.