Aerial algae were sampled from 28 sites on rocks, tree barks, and mosses along the Hongcheon-river in Gangwon-do, Korea, from December 2011 to September 2012 and then cultivated. Seven genera and eight species of the order Chlorococcales were newly recorded in Korea. These were Spongiococcum tetrasporum, Tetracystis aggregata, Myrmecia bisecta, Coenocystis inconstans, Lobosphaeropsis pyrenoidosa, Pseudococcomyxa simplex, Coelastrella oocystiformis, and C. vacuolata. As a result, the known Korean flora of the order Chlorococcales now includes 12 families with 54 genera, 263 species, 76 varieties, and 27 forma, giving a total of 366 taxa.