Kuyalnik Estuary (Ukrainian: Куяльницький лиман, Crimean Tatar: Kuyanlık) is an estuary of the Velyky Kuyalnik River located on the northwestern shores of the Black Sea, near the city of Odessa. The area of the estuary is 56-60 km², with a length of 28 km and a width of 3 km. Average depth is about 3 m. The estuary is separated from the Black Sea by a broad sandbar 3 km in width.