This study investigates the morphodynamic and sedimentary processes of the Moulay Bousselham coastline, a sandy stretch interrupted by the Merja Zerga lagoon inlet, designated a RAMSAR site. Conducted between 2017 and 2018, the research employs topographic profiling and sediment sampling to assess beach morphology, sediment distribution, and the influence of hydrodynamic forces. The results demonstrate marked spatial and temporal variability in beach morphology, with profiles exhibiting distinct responses to both seasonal and extreme hydrodynamic conditions. Northern beaches exhibit intermediate morphodynamic states, balancing energy dissipation and reflection, while southern beaches near the lagoon inlet display dissipative characteristics, absorbing wave energy and promoting sediment accumulation. The study highlights the protective role of a rocky platform in mitigating wave energy and supporting sediment retention. However, annual sediment budgets indicate a general erosion trend, amplified by extreme hydrodynamic events, including the February 2018 storm, which caused extensive sediment loss. Sediment analysis reveals a uniform granulometric structure, dominated by well-sorted medium sands shaped by hydrodynamic processes. This research fills a critical gap in understanding the interplay of sediment dynamics and hydrodynamic forces in this region, providing a scientific basis for sustainable coastal management and highlighting vulnerabilities to natural and anthropogenic pressures.