Two marine harpacticoid species, Phyllothalestris sarsi Sewell, 1940 and Dactylopusia falcifera Willey, 1935 belonging to family Thalestridae are redescribed from South Korea, on the basis of the specimens of both sexes mainly from the washings of macroalgae at littoral rocky shore or sublittoral bottom sediments during the period from 1994 to 2000. They are new to Korean fauna, and this report is the first record for them in the Pacific Ocean.