The clarification of spatial-temporal patterns of phytoplankton from southern coastal waters during the period of March to November in 2004 was carried out. Total cell numbers were shown in 5,286 cells ml−1 on March and reached to encounter a peak of 27,775 cells ml−1 on July. Mean cell number was also shown in maximum of 1,587 cells ml−1 on July, which recorded approximately two times higher than on June. The cell number of phytoplankton from southmiddle waters attained an abundance of ≥35 regardless of months, which was the highest the abundance of phytoplankton in 2004 than any other waters in this study. Southwestern waters were lower the cell number of 2-5 times than those of southmiddle and southeastern waters. In particular, Prorocentrum occurred in southeastern waters on June and the highest cell number of 8,200 cells ml−1 around Tongyeong region on July, which was recorded to occupy the value of 60.9% in southeast waters. The abundance of Skeletonema costatum as a dominant taxa in southwest was shown in ≥60 on March, July, September, and October, whereas was also recorded to achieve the abundance of above 80% in southmiddle waters on March, July, and September. The majority of the taxa in southeastern waters was diatom: Eucampia zoodiacus, and Chaetoceros spp.. They occupied above 45%. On November, most of southern waters were abundant to Chaetoceros spp. On the basis of cluster analysis using SPSS ver 10.0, phytoplankton occurring on March showed somewhat no correlation with all of southern waters. In contrast to on March, the relationship between southwestern and southmiddle waters was shown on August and November, indicating a distinction from southeastern waters. However, the distance between southwestern/middle and southeastern waters appeared to be less than 5. Consequently, the abundance of phytoplankton in southern waters showed much fluctuations in temporal and spatial assays. In particular, southwestern and southmiddle waters during the periods of summer and winter appeared to be a similar to environmental characteristics.