Seas & Oceans Bordering Russia

Arctic Ocean: Kara Sea, Barents Sea, Laptev Sea, East Siberian Sea, Chukchi Sea

Pacific Ocean: Bering Sea, Sea of Okhotsk, Sea of Japan

Atlantic Ocean (via marginal seas): Baltic Sea, Black Sea, Caspian Sea (inland), White Sea

Also: Barents Sea appears in both Arctic & Atlantic lists due to definitions. Russia has the world's longest coastline.