Large offshore wind-farm clusters impose spatially heterogeneous momentum forcing on the sea surface, but how the resulting wake-scale stress anomalies reorganize the ocean surface boundary layer over tropical–subtropical shelves remains poorly understood. We investigate the eastern Guangdong shelf in the northern South China Sea, where existing and planned wind farms form a southwest–northeast corridor that can align with the prevailing monsoon. A three-level nested COAWST system is used to compare no-wind-farm, present-layout, and expanded-layout experiments under representative summer southwesterly and winter northeasterly monsoon conditions. Turbine effects are represented primarily through atmospheric momentum extraction and wake-generated turbulence, whereas foundation-induced drag is treated only as a secondary sensitivity. Preliminary WRF simulations of representative coastal-breeze cases show that large wind farms reduce near-surface winds within the farm by up to 1.4 m s⁻¹ while enhancing downstream winds by more than 1 m s⁻¹. Adding far-offshore developments broadens the affected region and yields an additional downstream enhancement of 0.6–0.8 m s⁻¹. These sharp spatial gradients generate realistic perturbations in surface wind stress and wind-stress curl, thereby aiding the diagnosis of oceanic boundary-layer adjustment. The coupled experiments evaluate changes in Ekman transport and pumping, mixed-layer depth, stratification, turbulent kinetic energy, sea-surface temperature, vertical exchange, and cross-shelf transport. Particular attention is given to the interaction of wake-induced stress curl with monsoon background flow and coastal density fronts, including whether local upwelling–downwelling cells and enhanced mixing aggregate into a regional response along the wind-farm corridor. Sensitivity to wind-farm scale and turbine spacing is further assessed. By linking array-scale atmospheric momentum extraction to small-scale mixing, frontal adjustment, and vertical exchange, this study provides a process-based framework for evaluating the cumulative impacts of offshore wind on shelf circulation and marine spatial planning.