Sediment transport patterns in the northern South China Sea were studied by analyzing grain sizes of surface sediments. Three hydrodynamic provinces were identified based on sediment dispersal patterns: Province A with high traction near Taiwan and Hainan, Province B with saltation and graded suspension along the northern slope, and Province C with settled sediments near Luzon Island. The sediment transport route near the mainland follows marginal channels, while in deep water regions, it flows along isobaths. This study shows that analyzing grain size components and sortable silts in surface sediments can help understand modern hydrodynamic conditions and transport processes in marine environments.