The present paper aims at studying and comparing Bantu languages spoken along the Cameroonian, Equatorial Guinean and Gabonese coasts called the Sawabantu languages by reconstructing proto-Sawabantu (consonants and vowels) via the Comparative Method used in Historical Linguistics. The proto-Sawabantu reconstructions obtained are analyzed and compared with other proto-languages reconstructed for languages spoken in this region: proto-Bantu and proto-Manenguba in order to identify Sawabantu lexical innovations and phonological innovations. The resulting historical analyses shed new light on the fascinating history of the speakers of this particular region where the great Bantu Expansion started 5,000 years ago in southern Cameroon.