Examination of the qualitative and quantitative composition of the micro-and nannoplankton community in coastal waters near Nieuwpoort-Lombardsijde. 9 stations were sampled monthly during 2 years (23 campaigns between 12 May 1970 - 16 May 1972). The dataset describes overall species richness and species were classified in 6 density classes according to the number of cells per liter. Numerical productivity is given for following taxa: Ciliata, Centrales, Pyrrophyta, Nannoflagellata and Pennales. Total plankton biomass was calculated depending on average plasma volumes of the cells. Chlorophyll a concentration was determined spectrophotometrically for 108 samples.