This third paper in a monographic series on the marine macroalgae of French Polynesia gives a detailed coverage of the species of Rhodophyta occurring in these islands. A total of 197 taxa are presented (195 Rhodophyceae, 1 Phaeophyceae and 1 Chlorophyta; of these, 84 (or 43%) represent new records for the flora, while 7 (or 3.6%) are new species. The new combination Jania subulata (J. Ellis et Solander) N’Yeurt et Payri is made for Haliptilon subulatum (J. Ellis et Solander) W. H. Johansen. Padina stipitata Tanaka et Nozawa (Phaeophyceae) and Codium saccatum Okamura (Chlorophyceae) are notable additions to the flora from deepwater habitats in the southern Australs; 56 taxa (or 28.7%) occur only in the Austral archipelago. The flora has most affinities with that of the Hawaiian Islands (Sørensen Index = 0.30), followed by the Cook Islands and Samoa (SI = 0.26 each) and the Solomon Islands (SI = 0.25). There are some disjunct distribution patterns for several subtropical to temperate species, possibly suggesting special oceanic current routes between the southern Australs, Hawaii and the Southern Australian region.