Plocamium is a genus of red algae in the family Plocamiaceae. It contains around 40 species and has a cosmopolitan distribution in temperate seas, although it is most diverse in the southern hemisphere. It is widely distributed in tropical and also warm-temperate and cold-temperate seas, such as northern Europe, the northern Arabian Sea and western Australia. They are also found in the Antarctic regions of Admiralty Bay (maritime Antarctica, Antarctic Peninsula) and Terra Nova Bay (in the Ross Sea).