The paper analyzes data from 10 expeditions performed in the northwestern part of the Sea of Japan (36°–47° N, and 130°–141° E) including the coastal waters of Russia during the period from February to November in 2000–2015 which made it possible to consider the features of primary production in different seasons. For the analysis we used ship derived data on CTD, nutrients, chlorophyll a (Chl) and satellite remote sensing data. In the beginning of spring period maximum values of Chl and P are observed at the surface, while starting from May, after the establishment of summer stratification, the bulk of Chl and P are concentrated in the subsurface layer of 20–40 m. In autumn, in mid-October, the destruction of summer stratification begins and the supply of nutrients to the euphotic layer increases, as a result of which the content of Chl increases too. The value of annual P according to ship measurements is about twice as high as the satellite estimate, 400 and 224 gС/m2 y, respectively. The reason for this difference, in our opinion, is a combination of factors: an underestimation of the assimilation number in the cold season; unavailability of registration for the deep Chl satellite during summer stratification and underestimation of the thickness of the euphotic layer.