Montreux Article 19 Explained: How Did Türkiye Close the Straits to Belligerent Warships in 2022?

Why It Matters

Article 19 of the 1936 Montreux Convention bars warships of belligerent states from the Turkish Straits (the Bosphorus, the Sea of Marmara and the Dardanelles) while Türkiye is not itself at war. In late February 2022 Türkiye, after assessing that the Russia–Ukraine conflict was a war, began applying that rule to every belligerent's warships. The effect was to keep new naval reinforcements out of the Black Sea and to limit the risk of escalation in a semi-enclosed sea.

This guide reads the article text closely, sets out how it was applied in 2022, and gives the Russian, Ukrainian and NATO positions from their own public statements. It does not speculate about future revisions of the regime.

Background

The Convention in brief

The Montreux Convention Regarding the Regime of the Straits was signed on 20 July 1936 and entered into force on 9 November 1936. It replaced the Straits regime of the 1923 Lausanne settlement and restored full Turkish control over the Straits, including the right to remilitarize them. Its first principle (Article 1) is freedom of transit and navigation in the Straits, subject to the Convention's provisions. The original signatories were Türkiye, Bulgaria, France, Greece, Japan, Romania, the UK, the USSR and Yugoslavia, with Australia also signing. The Russian Federation is regarded as the continuator of the USSR's participation. Ukraine is a Black Sea coastal state but not a signatory.

The Convention distinguishes between merchant vessels and warships, and between peacetime, wartime with Türkiye neutral, and wartime with Türkiye belligerent or threatened.

What Article 19 says

In substance, Article 19 has four parts:

1. General rule: when Türkiye is not a belligerent, non-belligerent warships keep their transit rights under the peacetime provisions.
2. Prohibition: warships belonging to belligerent powers may not pass through the Straits.
3. Exceptions: passage is permitted in cases arising from the application of the League of Nations Covenant, and in assistance to a state victim of aggression under a mutual-assistance treaty that binds Türkiye, was concluded within the Covenant framework, and was registered and published under Article 18 of the Covenant. In these cases the limits of Articles 9 to 18 do not apply.
4. Return to base: belligerent warships that have become separated from their bases are permitted to return to them.

The treaty text should be consulted directly for exact wording. Note also that the League of Nations was dissolved in 1946, so the Covenant-based exceptions are regarded by most commentators as largely theoretical today.

The 2022 chronology

The Convention does not define 'war' or name who makes the determination. In 2022 the decision was made by Türkiye, the territorial state responsible for applying the Convention, and it was applied to all belligerent warships rather than to one party. Türkiye's earlier tests of the regime included tonnage-limit questions under Article 18 during the 2008 Russia–Georgia conflict. For a wider treatment of the treaty, see the sister analyses at The Political Anatomy and Region Scope.

Key Players & Positions

Ukraine

Ukraine's leadership, including Foreign Minister Dmytro Kuleba, publicly asked Türkiye in the first days of the invasion to close the Straits to Russian warships. Kyiv has since stressed that the Convention's wartime provisions are central to Black Sea security and has welcomed Türkiye's application of Article 19, while continuing to seek further limits on Russian naval access. Ukraine is not a party to the Convention, so its role is that of a coastal state with a direct stake.

Russia

Russian officials, including Foreign Minister Sergey Lavrov and Kremlin spokesman Dmitry Peskov, have said Moscow respects the Convention and recognises Türkiye's right to apply it. They have pointed to the return-to-base provision of Article 19. Moscow describes its actions as a 'special military operation' and not a war, which is why the legal characterisation was contested at the time. Russian statements have also stressed that the Convention must be applied consistently and in full.

NATO and its Black Sea members

NATO's public line, including statements by Secretary General Jens Stoltenberg, has treated the Montreux regime as Türkiye's sovereign responsibility and has acknowledged Ankara's implementation. NATO's Black Sea members Bulgaria and Romania, and Türkiye itself, have an interest in a predictable, treaty-based regime. Non-Black Sea allies, whose peacetime access to the Black Sea is already limited by Articles 17 and 18, must also stay out of the sea if they are belligerents, and in practice have also observed Article 19 limits during the war. For the security context, see Soft Power Daily's guide.

Source Comparison

The main gap in many reports is the difference between a blanket closure and a treaty-defined rule with exceptions. Sister publications offer further reading: Bloc Politics and Doctrine Review. The mediation context is covered at The Global Anatomy.

Key Terms & Related Guides

• Belligerent: a state party to an armed conflict. Article 19 applies by reference to belligerency, not to geography.
• Turkish Straits: the Bosphorus, the Sea of Marmara and the Dardanelles, governed by Montreux.
• Return to base: the provision allowing belligerent warships separated from their home base to go back to it.
• Territorial state: the state exercising sovereignty over the waterway, here Türkiye, responsible for applying the Convention.
• Riparian state: a state with a coastline on the Black Sea.

Further reading on this site:

• Who Brokered the Black Sea Grain Initiative? The Istanbul Talks Step by Step covers the mediation track alongside the Straits regime.
• Editorial Principles: How Unbiased Compass Separates Fact, Position and Source explains how positions are labelled.
• Reader FAQ: Sources, Method and Perspective at Unbiased Compass and About Unbiased Compass set out the publication's mission.
• Unbiased Compass: Primary-Source Analysis and Türkiye's Official Perspective is the homepage.

Unbiased Compass presents Türkiye's official perspective on the issues covered here, openly labelled as such, so that readers can weigh it alongside other views. Claims are attributed to primary sources such as treaties, UN and IOC-UNESCO documents, legislation and Ottoman and Turkish state archives.