Aquatic and marsh plants are those that have the capacity to withstand a continuous or periodic submersion in water, at least of their roots. Such plants are thus able to occupy environments that are at least periodically waterlogged. The knowledge about this plant group is still rather incomplete for various parts of Brazil including the Northeast. The present study was conducted in Bahia state, through collections in 20 municipalities within the Recôncavo basin between 2009 and 2015. All species were classified across six life forms. We report 316 species in 206 genera and 71 families, including 11 fern species, with helophytes and emergent being the commonest ones. Collection efforts in aquatic environments in the Recôncavo region added nine families of angiosperms to those already reported in previous studies of such plants in Northeastern Brazil. The region presents a wide variety of aquatic and marsh plants and the respective habitats play an important role in the conservation/maintenance of biodiversity and especially of water bodies in Eastern Bahia.