Start-up of plant for liquid gas production in Sabetta town (Russia, Yamal Peninsula) demands creation of the marine transport system for the gas shipment. The town is the significant cluster for the gas processing and export from South-Tambey field. The field stock is estimated in more than 1 trillion cubic meters of natural gas. Ice cover is a source of possible accidents with tankers. The accidents can lead to environment contamination. There is considered analysis of the intra- and inter-annual variability of ice conditions on the navigation route "Sabetta seaport – Kara Gate – Murmansk seaport" for the period of 1997-2018. The route is a path for export of liquid gas. It has processed electronic ice maps of the archives of the Arctic and Antarctic Research Institute (AARI). The maps of the archive were created by the vectorization of satellite images. The lengths of the route in close floating ice with presence of thick, medium, thin first-year ice, grey-white, grey and new ice, and with partial concentrations of thick and sum of thick and medium first-year ice equal to 5-10 tenths have been obtained for 24 decades from November to June. There has been carried out tests of homogeneity of the lengths inter-annual series by means of the method of integral curves and nonparametric Wilcoxon-Mann-Whitney and Siegel-Tukey criteria. Improvement of ice conditions along the route is revealed.