An investigation of the floral diversity of the littoral vegetation of Akwa-Ibom State coastline of South eastern Nigeria was carried out using quadrat and transects techniques. The results revealed three (3) vegetation types viz: coastal/shoreline, mangrove and secondary forest vegetation. Although, the most encountered ecosystem was the mangrove yet, coastal vegetation had the highest flora diversity of 100 (47%) as compared to mangrove and secondary forest with 87 (41%) and 27 (12%) species, respectively. A total of 147 taxa belonging to 134 genera and 58 families were recorded from the study area. The dominant family was Fabaceae with 17 species (29.3%), while the dominant genus was Ipomoea with 5 species (3.73%). Of these taxa, 59 occurred in more than one vegetation type while 11 were present in all the three (3) vegetation types. Phanerophytes are the dominant life form covering 36% (53 species) of the encountered species. Similarly, diversity index revealed the highest diversity of species in the coastal ecosystem with Shannon-wiener’s, Simpson’s and Margalef values of 0.99, 4.61 and 21.67, respectively. Correlation matrix and Jaccard similarity coefficient value (0.35) was high between the coastal and mangrove pairs; however, it depicts a minimal significant difference in the species composition within the three ecosystems at 0.05% probability level. Also, PCA scatter plot established less variation between the coastal and mangrove vegetation. Also, 16 economic plants were encountered during the study with uses ranging from edible fruits, spices, vegetables, root crop, and medicine, to palm wine. Factors affecting species distribution are introduction of alien species (Nypa fruticans), canalization, dredging, over exploitation of mangrove and pollution. Conservation status of these taxa according to IUCN 2014-2 showed that no endangered species was encountered during the study. However, conservation of this littoral vegetation is highly imperative in other to stabilize the ecosystem dynamics, protect the biodiversity, prevent or reduce potential effects of ecological disasters such as flooding and erosion. Key words: Littoral vegetation, flora, diversity, ecosystem, conservation.