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.
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.
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.
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.