This chapter addresses the relations between inlet dynamics and nearshore wave regime at a coastal lagoon in the Atlantic coast of Morocco. The study of wave climate indicates a southward trend for the net annual longshore sediment transport, which modifies previously reported conclusions fundamented upon limited series of observations on waves and interpretation of the inlet geomorphology. The snapshot images used here to characterize the morphodynamic behavior of the inlet indicate that its mobility is driven essentially by the northward component of the wave-borne longshore energy flux and transport, thus bearing no direct relation with the net annual residue of longshore energy flux and sediment transport; we interpret this as a result of contrasting effectiveness in early wave energy dissipation induced by shoal fields populating the nearshore north and south of the inlet. Moulay Bousselham inlet illustrates a case where geomorphological interpretation of coastal features may be insufficient to support inferences on coastal hydrodynamics.