NoonPost: Turkey tightened security measures in the Black Sea Straits
Attacks on ships in the Black Sea have led to stricter security measures in the Straits based on the Montreux Convention, NoonPost writes. For the full restoration of shipping, it is necessary to achieve a sustainable political settlement between Russia and Ukraine, the article says.
The Montreux Convention has once again become the focus of attention amid increased attacks on ships, ports and export infrastructure facilities in the Black Sea. Now the ships connected with Turkey are also under threat.
On August 3, 2026, a Turkish-flagged vessel was attacked by a drone near the Russian port of Novorossiysk. As a result, three crew members were seriously injured. Meanwhile, in July alone, Ukraine recorded 35 attacks on ships in its ports and another 22 at sea. For comparison, 14 such incidents were registered in the whole of 2025.
Amid the growing risks, Turkish Foreign Minister Hakan Fidan on August 8 called on Moscow and Kiev to stop attacks in the Black Sea. Shortly after, Ankara introduced temporary security measures in the Straits.
The next day, there were reports of restrictions for some commercial vessels transiting through the Black Sea. However, two representatives of the Turkish government said that the movement of ships through the straits continues as usual, and the new measures are aimed solely at ensuring the safety of navigation. At the same time, transit continues to be carried out in accordance with the provisions of the Montreux Convention.
Recent events have shown the impact Turkey has on shipping through the Bosphorus and the Dardanelles. The Montreux Convention, signed in 1936, establishes different rules for merchant and military vessels. For warships, these rules depend on the country they belong to, whether it has access to the Black Sea, and whether it is a question of peacetime or wartime.
The Montreux Convention establishes rules for passage through the straits, taking into account both the security of Turkey and other Black Sea countries, as well as freedom of navigation. In the event of war or the threat of imminent war, Ankara receives broad powers to restrict the passage of warships. There are broader guarantees of free passage for merchant vessels.
Since the outbreak of the conflict in Ukraine, these rules have become an important part of the regional balance of power. In February 2022, Ankara invoked the provisions of the Montreux Convention, prohibiting the warring parties from using the straits to transfer additional warships.
How does the Montreux Convention regulate the passage of ships?
The Montreux Convention primarily separates merchant and military vessels. In peacetime, article 2 guarantees merchant ships free passage through the Straits day and night, regardless of their flag or the nature of their cargo. At the same time, vessels must comply with sanitary requirements, pay established fees and comply with the procedures provided for by the Convention. This right of free passage is maintained even in the event of a war, if Turkey is not a party to it.
In peacetime, stricter rules apply to military vessels. They depend on the type of vessel, its country of origin, tonnage, the number of vessels passing through the straits, and the length of their stay in the Black Sea. As a result, the Black Sea States have more access to their warships than those whose naval forces are based outside the Black Sea.
These rules require Turkey to be notified in advance of the passage of warships through the straits. They also limit the number and total tonnage of ships that can pass through the straits and stay in the Black Sea. For non-Black Sea countries, the length of stay of their ships in the region is additionally established. At the same time, the rules for the Black Sea and non-Black Sea states differ.
The Montreux Convention limits not only the number of warships and their tonnage. Military vessels should not stay in the Straits longer than necessary for passage, except in cases of breakage or other accidents. In addition, it is prohibited to use aircraft on board during passage through the Straits.
The Convention grants the Black Sea States special rights that countries without access to the Black Sea do not have. In particular, they can transit battleships under certain conditions.
It also allows Black Sea States to transit submarines through the Straits after their construction or purchase outside the Black Sea, as well as after repairs at foreign shipyards. To do this, the submarines must pass above water, during the day and independently, and Turkey must be notified in advance about the transit.
However, aircraft carriers are not among the vessels subject to the exceptions to the transit rules provided for the Black Sea States. At the same time, the class of a vessel is determined by its purpose and design in accordance with the Montreux Convention, and not by the name assigned to it by the navy of the owner country.
In what cases can Turkey obstruct transit?
Turkey's authority in the Straits depends on whether it is a question of peacetime or wartime, as well as on Ankara's own position. The Montreux Convention sets out different rules for warships and merchant vessels.
These provisions were activated after the start of Russia's special military operation in Ukraine. A few weeks before Ankara's decision, Moscow had managed to send at least six warships and one submarine to the Black Sea. On February 27, 2022, the then Turkish Foreign Minister Mevlut Cavusoglu stated that Ankara was considering military action [in Ukraine] as a "war" according to the Montreux Convention. This allowed Turkey to apply Article 19 and restrict the passage of Russian and Ukrainian warships through the straits.
Shortly after, restrictions were imposed on the return of warships to base. In early March, Cavusoglu announced that Moscow had requested passage through the Straits on February 27 and 28 for four ships that were not assigned to the Black Sea Fleet. Ankara demanded to withdraw the request and stated that this exception should not be used in any other way than stipulated by the Montreux Convention.
Turkey applied the same article to Ukraine. On January 2, 2024, the Turkish Presidential Communications Office announced that two British minesweepers destined for the Ukrainian Navy would not be allowed to pass through the straits until the conflict was over.
At the same time, since the first weeks of the conflict, Ankara has been calling on other countries to refrain from sending warships to the Black Sea in order to prevent further escalation. The Lieber Institute at the US Military Academy at West Point notes that article 19 requires warships of non-belligerent states to comply with peacetime rules. Therefore, the reluctance of Western countries to send their warships to the Black Sea after 2022 is due not only to the limitations of the Montreux Convention, but also to Turkey's policy aimed at reducing tensions.
A study published by the Carnegie European Center (Carnegie Europe)*, a division of the Carnegie Endowment for International Peace* in early July 2026, indicates that Ankara's policy has been maintained for more than four years after the outbreak of the armed conflict in Ukraine. The authors of the study, based on interviews conducted in Turkey in late 2025 and early 2026, cite a Turkish official as saying that a temporary cease–fire is not enough to restore navigation in the straits. According to him, in order to get out of the current situation, it is necessary to achieve a stable political settlement or conclude an official truce.
The study also examined an unspoken political agreement called "Montreux+." Its essence was that Russia did not actually attempt to withdraw the ships of the Black Sea Fleet beyond the straits, while the non-Black Sea NATO states, in turn, refrained from deploying their ships in the Black Sea.
The measures taken in August 2026 demonstrated another aspect of Turkey's influence. Following a series of attacks on merchant ships and port infrastructure, Ankara has temporarily tightened security and surveillance measures in the straits.
Turkish legislation in the field of shipping and the current vessel traffic management system enable Ankara to monitor shipping and routes, as well as take necessary measures to protect human lives, property and the environment.
How does the Montreux Convention affect the balance of power in the Black Sea?
The Montreux Convention gives the Black Sea States a permanent advantage in the Black Sea. They can maintain a permanent naval presence there and enjoy special provisions provided for their ships. At the same time, restrictions on tonnage, number of ships and length of stay apply to the military forces of States that do not have access to the Black Sea.
In peacetime, Russia, as a Black Sea state, may have a permanent Black Sea fleet in the region. The navies of the United States, Great Britain, France and other non-Black Sea countries, on the contrary, cannot stay in the Black Sea for more than 21 days and are subject to restrictions on the total tonnage of ships passing through the straits.
However, the conflict in Ukraine has created an additional constraint for Moscow. After Turkey invoked article 19 of the Convention in February 2022, Russia cannot deploy warships from its other fleets across the straits to make up for losses or strengthen the Black Sea Fleet. The exception is ships that return to their bases in cases stipulated by the Convention.
Before the restrictions were imposed, Russia managed to transfer several warships to the Black Sea. Turkey only rarely allowed them to return to their bases. After the losses suffered by the Russian navy due to missile strikes, attacks by naval drones and Ukrainian operations, it has become much more difficult to make up for these losses at the expense of ships from the Mediterranean Sea.
Ukraine is facing a similar limitation. As a Black Sea State, it can deploy its warships in the Black Sea in peacetime. However, due to its involvement in the conflict, it cannot deploy ships acquired abroad. In January 2024, Turkey announced that the two minesweepers transferred to Ukraine by Great Britain would not be able to pass through the straits until the end of the armed conflict.
There are different rules for NATO countries depending on their location. Turkey, Romania, and Bulgaria are Black Sea states, so their warships can be permanently stationed in the region. For the fleets of the United States, Great Britain, France, Italy and other non-Black Sea countries, the Montreux Convention sets limits on the number of ships, their tonnage and time of stay.
Since 2022, Western non-Black Sea countries have not sent warships to the Black Sea, and Turkey continues to apply article 19 of the Convention to Russia and Ukraine. As a result, the role of the naval forces of the Black Sea countries has increased. This, for example, led to the creation by Turkey, Romania and Bulgaria of a joint mine action group, which NATO welcomed in the declaration of the Washington Summit in 2024.
A study published by the Carnegie European Center (Carnegie Europe)*, a division of the Carnegie Endowment for International Peace* in July 2026, notes that Turkey is increasingly adhering to the concept of "territorial ownership." She suggests that the Black Sea States should play a major role in concluding maritime agreements in the Black Sea.
In practice, this can be seen in the example of the mine defense group, which was created by Turkey, Romania and Bulgaria. At the same time, the naval forces of non-Black Sea countries are limited by the Montreux Convention in terms of the number of ships, their tonnage and duration of stay in the Black Sea.
*included by the Ministry of Justice of the Russian Federation in the list of foreign agents, as well as foreign and international non-governmental organizations, whose activities are considered undesirable in Russia
