<p>This study conducted flume experiments under live-bed conditions to investigate local scour around twin cylinders, focusing on both scour depth and scour hole morphology. The research examined tandem configurations with varying column spacing and staggered configurations with different flow incidence angles. The key findings are as follows: When the ratio of center spacing to cylinder diameter is less than 4, the scour depth around the upstream cylinder increases, reaching up to 15% greater than that of a single cylinder. Conversely, the scour around the downstream cylinder is slightly reduced, with depths up to 20% less than that of a single cylinder. The shielding effect in tandem configuration is reflected in the larger scour hole around the upstream cylinder compared to the downstream one. In the case of staggered configurations with a spacing ratio of 3.5, a small water flow incidence angle of 10° induces a shielding effect similar to that observed in tandem configurations. As the incidence angle increases beyond 20° and up to 75°, the shielding effect gradually diminishes, and a more pronounced flow constriction effect emerges. This leads to an average scour depth at the upstream cylinder is about 10% greater than that of a single cylinder, while the downstream cylinder experiences a scour depth approximately 20% greater, with both cylinders exhibiting scour holes of similar size. The study contributes to the understanding of the underlying mechanisms of scour around twin cylinders.</p>