The coast of Namibia (South West Africa) which lies partly within and partly outside the tropics on the south western Atlantic coast of Africa was visited and studied in July 1957. Littoral zonation at three main localities (Liideritz, Elizabeth Bay, and Swakopmund) is briefly described, and an annotated list is presented of the 136 species of marine algae now known from Namibia, as well as of certain algae identified only to genus.