The Ouladine lagoon has an irregular bottom lined with different substrates. The lithological characteristics make it possible to observe sediments ranging from silts to sands and mixed sediments of variable color. These different fractions have varying proportions. The coarse fraction (>63 μm) has percentages ranging from 0 to 77% and the fine fraction (<63 μm) from 22.46 to 100% in the different sediments collected. The minority fraction of fine sands occupies the northern banks where the greatest depths of the section parallel to the coastal strip are observed. On the other hand, the sandy fractions occupy the southern shore up to the vicinity of the Azuretti mangrove island. This sandy fraction is also present on almost the entire section from the Comoé-Ebrié lagoon confluence to the closed mouth. The grain size characters of the sediments, such as the diagram of the classification coefficient So and the mean Mz, show well-classified sands. These sediments are deposited in a slightly agitated environment coming mainly from dunes and rivers. The sands of the estuarine complex were emplaced by saltation for most samples and by rotation.