Diel vertical migration (DVM) and distributional patterns of copepods collected in the water column at shallow water site (Station M) in Tanabe Bay, Japan were investigated. Twenty-one taxa of zooplankton and 48 species of copepods at Station M had positive ΔZ values (subtraction of night-time weighted mean depth from daytime value) and performed normal DVM. The highest ΔZ value was 4·3 observed in Ambunguipes rufocincta. Three taxa and 39 species collected only at night also had high WMD (weighted mean depth) values (4·0∼7·5), which were previously considered hyperbenthic species. Statistically significant differences were found only in Myodocopina spp., Calocalanus plumulosus and Clausocalanus spp. Myodocopina spp. and Clausocalanus spp. showed downward migration at low to high and high tidal phases. Calocalanus plumulosus and some copepods performed downward migration during high and high to low tidal phases. Four distributional patterns of copepod species in Tanabe Bay were found. The groups are as follows: (A) true planktonic group; (B) swarming and night emerging group; (C) night emerging meiobenthic and hyperbenthic group; (D) symbiotic and night emerging group.