Mobile Bay, Alabama, has served as an introduction site for several invasive species, including the red imported fire ant, Solenopsis invicta. Here we present evidence for the introduction of an exotic red alga, Grateloupia taiwanensis S.-M.Lin and H.-Y. Liang, to Mobile Bay, using the rbcL genetic marker to assist in identification as well as phylogenetic analysis. We have also sequenced the plastid and mitochondrial genomes of this alga.