Bosporus Transit File 2026, Montreux Rules and Black Sea Traffic

This is a status file for the Bosporus in 2026. It tracks what is moving through the strait this year and how Ankara is using the 1936 treaty that governs the passage, while the sea to the north turns into a war zone. The standing rules (traffic lanes, pilotage, the lighthouse fee) are set out in our guide to ship traffic and transit rules. This file deals with the numbers and the war.

Start with the baseline. Turkey's transport ministry counted 40,172 Bosporus transits in 2025, part of a record 84,640 for the Turkish Straits as a whole. Those ships carried 422.8 million tons of cargo through Istanbul, and 203.7 million tons of it was classed as dangerous: crude, fuel, chemicals, gas. About 61 percent of the ships took a Turkish pilot.

The 2026 count so far

The year started slightly slower. In the first quarter 9,195 ships passed the Bosporus, about 102 a day and 1.7 percent fewer than a year earlier; not one of them was longer than 300 metres. By the end of April the count was 12,565, of which 2,961 were tankers. The half-year total came to 19,277 ships against 19,381 in the first half of 2025, a drop too small to call a trend.

Tonnage went the other way. Gross tonnage through the Bosporus rose to about 301.5 million in the first half, up from 291.7 million, and big ships came back in the spring: 26 vessels over 300 metres went through between April and June. The tanker share is the number that matters to the people living on the shores. In six months the ministry logged 3,201 oil and other tankers, 899 chemical tankers and 392 liquefied gas carriers, close to a quarter of all traffic. Pilot use rose to about 64 percent. The month-by-month detail is in our first-half traffic report.

The same table carries a smaller line that says more about politics than about commerce. Twenty warships passed the Bosporus in those six months, against more than 100 merchant ships on an average day.

At the time of writing, the latest published breakdown covers January to June. The third quarter will be the real test, because that is when the war at sea changed.

What the war did to the cargo

Two flows dominate the Black Sea's southbound traffic: Ukrainian grain and Russian and Kazakh oil. Both were hit hard in the summer of 2026.

Ukraine's sea corridor, opened in 2023 after Russia quit the UN grain deal, carried 86.2 million tonnes in 2025, and by late July 2026 it had moved more than 42 million tonnes, running about 20 percent ahead of the year before. Then Russia went after the ships. Odesa prosecutors counted 28 commercial vessels struck in a single month to late July, with 21 seafarers and port workers killed. On 23 July Ukrainian officials reported no ships moving on the corridor at all, the first such day since it opened; shipowners, not the government, had made the call. Traffic came back slowly. In mid-August three or four ships a day were moving in and out of the Odesa ports, a quarter or a third of the earlier pace, and grain loadings in the first twelve days of the month were about 590,000 tonnes.

Russian oil took its own beating, from Ukrainian drones hitting tankers, the Novorossiysk terminals and the Caspian Pipeline Consortium's moorings. S&P Global's tanker tracking put Russia's Black Sea crude exports at 849,900 barrels a day in July and 380,300 in August, a fall of more than half. CPC loadings, which carry most of Kazakhstan's oil, were already down to about 1.3 million barrels a day in July, some 600,000 below May. Turkey itself bought less: its imports of Russian Urals crude were about 161,000 barrels a day in May 2026, against 302,000 a year earlier.

Much of what Russia still ships out of Novorossiysk and Tuapse rides on its shadow fleet, ageing tankers with obscure owners and insurers, every one of which must sail past Dolmabahçe and Rumeli Hisarı on the way out (see the shadow fleet in the straits). Turkey's one serious check on them dates from December 2022, when it demanded insurers' letters for laden tankers and held up more than twenty ships for days before a deal with the P&I clubs. A Carnegie Europe paper in July 2026 suggested Turkey use the convention's sanitary-inspection clause to board the worst of these ships before they enter the strait. Ankara has shown no interest.

Article 19, applied with a light touch and a long memory

On 28 February 2022 Turkey declared the Russia-Ukraine fighting a war and applied Article 19 of the Montreux Convention. Under it, warships of belligerent states may not use the straits, except to return to their home bases. Ankara went further than the text required and asked every government, Black Sea or not, to keep its warships out.

Four and a half years on, the closure is the most consistent thing about Turkish policy in the war. Turkey refused a Russian request to bring four warships into the Black Sea. In January 2024 it refused passage to two former Royal Navy minehunters that Britain had given Ukraine; they are still in Portsmouth. Turkish officials have said a ceasefire alone won't reopen the straits to warships, only a durable settlement. The Russian embassy in Ankara posted a reminder in April 2026 that the convention must be observed. The arrangement has its appeal in Moscow: Russia can't reinforce its own Black Sea Fleet, but no NATO navy from outside can reach the sea either.

Instead of outside navies, Turkey has offered regional ones. It runs a mine-clearing task group with Romania and Bulgaria, and in April 2026 it announced a maritime command in Istanbul to be led by the three coastal states. Turkey would sit at the centre of any Black Sea security system. That suits a government that likes to be the indispensable broker.

The commercial side has been handled less openly. In early August 2026, after drones hit the container ship Yanina on 1 August, the Turkish-flagged Nadezhda on 3 August and the Turkish dry-cargo ship Güllük off Novorossiysk on 7 August, the Directorate General of Coastal Safety quietly told ships bound for Novorossiysk, and some bound for Ukraine, that it wasn't issuing transit permits for now. No rule was published and the ministry wouldn't comment. The crude tanker Aegean Dream, heading for the CPC terminal, waited from 6 August until it was let into the Dardanelles on 9 August, when the hold was lifted. Foreign Minister Hakan Fidan meanwhile called on Moscow and Kyiv to declare a moratorium on attacks at sea.

Montreux gives merchant ships free passage in peacetime and in any war Turkey isn't fighting. A three-day hold by unexplained administrative silence is the kind of tool Erdoğan's government reaches for at home too. There is no decree anyone can challenge in court, and the result is hard to pin on anyone.

Insurance, and the hole in the middle

The war-risk market has moved faster than the diplomats. On 16 September 2026 the Lloyd's Joint War Committee extended its listed area to cover most of the Black Sea, leaving out only the 12-mile territorial waters of Turkey, Bulgaria, Romania and Georgia. Then drones began hitting ships in Romanian and Bulgarian economic zones. By 6 October the war-risk rate for a Black Sea voyage had gone from about 0.1 percent of a ship's value to 0.5 percent in two weeks, and brokers expect 1 percent. About nine in ten ships on the western run now hug the coast inside territorial waters to avoid the charge (the October strikes are covered in Black Sea shipping under fire).

Turkey's own charge keeps rising regardless. The lighthouse and rescue fee for ships passing without a port call went to 6.70 dollars per net ton on 1 July 2026, more than eight times the 2022 rate, set by presidential decision.

The last item in the file is the one that never moves. Canal Istanbul, Erdoğan's planned second strait on the European side, was again promised a tender in October 2026. No date was given and no financier named, and the 2026 budget gave it 10,000 lira (status here). Every tanker in this file went through the old strait.

We'll update the file when Ankara publishes the full-year 2026 numbers. For tanker traffic at the other end of the oil map, see hormuz.net.