Coastal dune wetland has an important ecological implication in that it could be closely related to the coastal dune ecosystem by providing various ecological habitats as well as ecological corridor. This paper aims to investigate the hydrological characteristics and aquatic biota of Mokgimiyeonmot (pond), coastal dune wetland in Gulupdo (island). Mokgimiyeonmot located in the lowland dune flat areas has six months long hydro period a year and can be categorized into wet dune slack type coastal dune wetland. As a result of this study, two species of freshwater fishes, two species of amphibia, and 35 species of benthic macro-invertebrates are recognized. Talitridae sp. belonging to Amphipoda also recognized in this survey for the first time from Korea. The results of this study are expected to be basic data necessary to understand the aquatic ecosystems and manage the ecological function of coastal dune field.