East Siberian Sea, Rus. Vostochno-Sibirskoye More, part of the Arctic Ocean N of NE Siberia, Russia, bounded on the W by the New Siberian Islands and on the E by Wrangel Island. The Indigirka, Kolyma, Chaun, and other rivers flow into the sea. The western section of the sea is very shallow. Ambarchik, NE Sakha Republic, is the main port on the sea, which is navigable during the ice-free days of August and September.