The results of studies of the current state of the lakes of the Samoylov Island (the Lena River delta) in winter are presented. Based on the results of sounding the water column, the features of the distribution of temperature, electrical conductivity of water, underice irradiation and dissolved oxygen at the end of the ice period were established. For the first time it was established that the lakes significantly differ by the degree of under-ice irradiation, which determines radiation heating and the possibility of developing under-ice convective mixing. The influence of river waters can be traced over a wide range of variability of the electrical conductivity of water in the lakes. It was established that the oxygen regime of the studied lakes in winter varies over a wide range from a pronounced oxygen deficiency to favorable conditions.