The East Siberian Sea (Russian: Восто́чно-Сиби́рское мо́ре) is a marginal sea in the Arctic Ocean. It is located between the Arctic Cape in the North, the coast of Siberia in the South, the New Siberian Islands in the West and Cape Billings, close to Gytkhelen, Chukotka, and Wrangel Island in the East. This sea is bordering on the Laptev Sea in the West and the Chukchi Sea in the East.
Since it is open towards the Arctic Ocean in the north, the main gulfs of the East Siberian Sea, like the Kolyma Bay, the Kolyma Gulf and the Chauunskaya Bay, are all located in its southern limits.
The area of the sea is 361,000 square miles. 70% of it is no deeper than 50 m, the deepest point being 155 m. The coast is mostly flat in the West (up to the mouth of the Kolyma), and mountainous in the East. Average air temperatures are 0°C to 2°C (4°C in the South) in the summer, reaching -30°C in the winter.
There are no islands in the middle of the East Siberian Sea, but there are a few islands and island groups in its coastal waters, like Ayon Island and the Medvyezhi island group.
Owing to its extreme northerly location the East Siberian Sea is most of the time covered with ice. The eastern coasts have some elevated terrain and hills, but the western coasts are mostly low-lying and covered with tundra, marshes and multitude of small lakes.
Among the rivers flowing into the East Siberian Sea, the Indigirka, the Alazeya, The Ujandina, the Chukochya River, the Kolyma, the Rauchua, the Chaun, and the Pegtymel are the most important.
The principal ports are Pevek and Logashkino. The latter was abandoned after navigation along the Northern Sea Route declined in the latter half of the 20th century. After the breakup of the Soviet Union commercial navigation in the Arctic went into decline. Nowadays more or less regular shipping is to be found only between Pevek and Vladivostok. Ports in the northern Siberian coast located between Dudinka and Pevek see next to no shipping at all.