Collections were made monthly using beam trawl from March 2005 to February 2006 in Gujora, and from June 2006 to May 2007 in Geoje Bay to investigate the species composition of Juvenile and Immature Fishes of both coastal areas. Fishes collected in the sandy shore of Gujora were 6 orders, 14 families, 20 species, 224 individuals, and 534.9 g in total. Favonigobius gymnauchen, Trachioncephalus myops, Pseudoblennius percoides, Sagamia geneionema, Repomucenus beniteguri, and Pseudorhombus cinnamoneus were mainly collected. These 6 species accounted for 83.9% of total individuals and 47.1% of total biomass. On the other hand, fishes collected in Geoje Bay were 4 orders, 8 families, 14 species, 1,406 individuals and 1,899.7 g in total. Acentrogobius pflaumii, Platyce phalusindicus, Chasmichthy dolichognathus, Acanthogobius flavimanus, Gymnogobius urotaenia, and Synechogobius hasta were mainly collected. These 6 species accounted for 97.7% of total individuals and 96% of total biomass. The greatest numbers and biomass of fishes were collected in summer and the lowest in winetr. In Geoje Bay, the number of species and individuals reached the peak in September and August, respectively. However, both species and individual numbers were highly fluctuated in Gujora.