This study reports on the intertidal and shallow subtidal brown algal flora from Hainan Island in the South China Sea, based on extensive sample collection conducted in 1990, 1992, and 2008-2016. The analyiss revealed 27 new records of brown algae for Hainan Island including 5 species which also constitute new records for China. 21 of these species are described with photographs and an annotated list of all species with information on life forms, habitat (localities and tidal zones) and their geographical distribution is provided