The grain size distribution and mineral composition of coastal sediments vary along the shoreline and beach profiles. This variation depends on several factors, including the sources of the sediments (such as rivers), the distance from these sources, and the direction of littoral drift. Additionally, harbors and water intakes can lead to downstream erosion, which impacts the texture of the sediments. Understanding these changes is essential for comprehending littoral drift and the impact downstream from harbors and river mouths. Understanding these changes helps to better understand the littoral drift and the impact extent downstream from harbors and river mouths. This article analyzes data from 539 sediment samples taken from the southern shoreline of the Caspian Sea, across 94 beach profiles and at 6 different depths.The findings confirm a general eastward direction of littoral drift and identify a specific sediment cell (from Sefidrud to Anzali) where the littoral drift direction contradicts this overall trend. The study also reveals that the length of the eroded shoreline downstream of the Nowshahr and Amirabad harbors (which are 74 and 33 years old, respectively) measures 28 km and 14 km to the east. These results are supported by hydrographic maps at Nowshahr and satellite images indicating beach retreat at Amirabad. Furthermore, the affected shoreline near the Sefidrud River has been identified. The heavy minerals found in the studied area predominantly include magnetite, goethite, rutile, and zircon. The concentration of heavy minerals generally decreases from east to west, which aligns with the overall direction of sediment transport.