Bosphorus and Dardanelles

The narrow Turkish straits that gate Black Sea trade, from Ukrainian grain to Russian and Kazakh oil.

Overview

The Bosphorus, at points under 700 meters wide, and the Dardanelles form the only sea exit from the Black Sea, governed since 1936 by the Montreux Convention, which gives Turkey control of passage and restricts warships. Strong currents and sharp turns make pilotage mandatory for large vessels. The straits carry a major share of world wheat and sunflower oil exports plus crude from Novorossiysk and Kazakh oil from the CPC terminal. The 2022 war brought mine risk, insurance spikes and the grain corridor ships that passed under wartime inspection regimes. Istanbul has grown up directly on top of one of the world's critical waterways.