Montreux Article 19 in Practice: Why Did Türkiye Close the Straits to Belligerent Warships in 2022?

Why It Matters

The Montreux Convention Article 19 belligerent warships clause decides who can send military vessels through the Bosporus and Dardanelles once a war begins. In February 2022, after Russia's full-scale invasion of Ukraine, Türkiye announced that it would apply that clause, which stopped the warships of all states at war from entering or leaving the Black Sea except in narrow cases. The decision shaped the naval picture in the Black Sea throughout the war and showed how a 1936 treaty still works as a live instrument of crisis management.

Background

What the Convention says

The Convention Regarding the Regime of the Straits was signed on 20 July 1936 at Montreux, Switzerland, and entered into force on 9 November 1936. It replaced the Lausanne Straits regime of 1923 and restored Turkish control over the Straits' security, including the right to remilitarize them. The parties included Türkiye, the United Kingdom, France, the Soviet Union (whose rights Russia continues), Greece, Romania, Bulgaria, Yugoslavia and Japan.

The structure is straightforward:

• Merchant vessels enjoy freedom of transit and navigation in peacetime (Article 2). Articles 4 to 6 adjust that regime for wartime depending on whether Türkiye is neutral, belligerent or under imminent threat.
• Warships in peacetime may pass under Articles 10 to 18. Black Sea powers get broader rights than non-Black Sea states. Non-Black Sea powers must give 15 days' notice and face tonnage and duration limits in the Black Sea (Articles 13, 14 and 18). Black Sea powers give 8 days' notice.
• Wartime with Türkiye neutral is governed by Article 19.
• Wartime with Türkiye belligerent, or Türkiye threatened by imminent danger of war is governed by Articles 20 and 21, which leave the passage of warships to Türkiye's discretion.

Article 19 in plain terms

Article 19 has four operative parts:

1. In a war in which Türkiye is not belligerent, warships of non-belligerent states keep freedom of transit under the same conditions as in Articles 10 to 18.
2. Warships belonging to belligerent powers shall not pass through the Straits. The exceptions are cases arising from the Covenant of the League of Nations, and assistance to a victim of aggression under a mutual-assistance treaty binding Türkiye and concluded within the League framework. The Convention text lists these two exceptions explicitly.
3. Belligerent warships that have become separated from their bases may return to them, whether the state is a Black Sea power or not.
4. Belligerent warships may not capture vessels, exercise the right of visit and search, or carry out any hostile act in the Straits.

The League-based exceptions are largely dormant, because the League of Nations no longer exists and the relevant treaties are historical. In practice the return-to-base clause is therefore the one that matters.

How the procedure works for a non-belligerent Türkiye

The Convention places the day-to-day administration of the Straits with Türkiye. When Türkiye is not a party to the conflict, the process runs as follows in practice:

• Türkiye makes a determination that a state of war exists between other states, which triggers Article 19.
• A state wishing to send a warship must give notice through diplomatic channels in the periods set by Article 13.
• Türkiye assesses the request against the Convention. A belligerent's warship is allowed only if the request clearly falls under the return-to-base clause or another recognised exception.
• Non-belligerent warships remain subject to the ordinary limits on tonnage, class and duration of stay.

The Convention does not define "separated from their bases" in detail, and it does not set out a documentary test. Ankara's published practice relies on the registered home port and the facts of each notified transit. For comparative analysis of this mechanism, see the explainers from sister publications such as The Political Anatomy on Article 19 and the Turkish Straits and Bloc Politics on how Türkiye governs Black Sea access.

Chronology of the 2022 decision

Date	Event
24 February 2022	Russia launches a full-scale invasion of Ukraine.
Late February 2022	Ukrainian officials publicly urge Ankara to close the Straits to Russian warships.
28 February 2022	Foreign Minister Mevlüt Çavuşoğlu announces that Türkiye will implement Article 19 and that it has informed relevant states.
March 2022 onward	Türkiye applies the restriction to all belligerent warships, with the return-to-base exception available.
22 July 2022	Russia, Ukraine, Türkiye and the UN sign the Black Sea Grain Initiative arrangements in Istanbul.
17 July 2023	Russia announces it is ending its participation in the grain arrangement.
11 January 2024	Türkiye, Romania and Bulgaria sign an agreement on a Black Sea mine countermeasures task group.

Key Players & Positions

Russia

Russian officials, including the Foreign Ministry and Kremlin spokespeople, have repeatedly described Montreux as a cornerstone of Black Sea security and said they expect it to be applied as written. Moscow has emphasised that the return-to-base clause protects vessels of Black Sea fleet units returning to their ports, and it has criticised the growing naval presence of non-littoral NATO states in the Black Sea. Readers should consult Russian Foreign Ministry briefings directly for exact wording.

Ukraine

Ukraine's government urged Türkiye in the first days of the invasion to close the Straits to Russian warships. Ukrainian officials, including the Foreign Ministry, have since welcomed Ankara's application of Article 19 while arguing that Russian naval activity in the Black Sea threatens commercial shipping and Ukrainian ports. Kyiv has also pressed for tighter enforcement of the return-to-base wording. Official statements are published on the Ukrainian Foreign Ministry website.

NATO and its member states

NATO officials and allied governments have said they respect the Convention's regime. The three NATO littoral states, Türkiye, Romania and Bulgaria, have different priorities. Romania and Bulgaria have supported a stronger Allied maritime posture in the Black Sea, within the limits of Montreux. The 2024 mine countermeasures arrangement among these three states was designed as a regional response to drifting mines. Allied statements can be checked in NATO summit communiqués and national ministry of defence releases.

Other treaty parties and shipping interests

Other signatories, including the United Kingdom and France, have repeatedly endorsed adherence to the Convention. Commercial shipping associations have focused on the distinction between warships and merchant vessels, since Article 19 does not restrict commercial transit. Insurers and shipowners have nonetheless responded to war-risk exposure in the Black Sea independently of the treaty.

🇹🇷 Official Policy · Primary Sources

Türkiye's Position

Ankara presents its application of Article 19 as neutral treaty implementation, rather than as a political choice for or against any party.

• The announcement was a legal determination. According to Foreign Minister Çavuşoğlu's statement of 28 February 2022, reported by Turkish official and state media, Türkiye assessed that the situation constituted a war and would therefore apply Article 19 in full. The Turkish Ministry of Foreign Affairs (MFA) publishes its summary of the Straits regime on its website.
• The rule applies equally to all belligerents. Ankara argues that Article 19 does not single out Russia or Ukraine. It restricts warships of every state at war, which is how the MFA has described the measure in statements and press briefings.
• The return-to-base exception remains in force. Türkiye has said that the Convention's third paragraph of Article 19 is part of the same text and must be respected, including for vessels that are separated from their bases. Turkish officials have said that each request is assessed by reference to the treaty wording and the registered base.
• Montreux is balanced and should not be reopened lightly. The MFA and the Presidency have described the 1936 regime as a framework that has preserved stability in the Black Sea for decades. Ankara argues that the Convention gives Türkiye responsibilities as guardian of the Straits, not a veto, and that it prevents the Black Sea from becoming an arena of naval confrontation.
• Neutral implementation sits alongside mediation. The restriction under Article 19 has run in parallel with Türkiye's diplomatic work, from the 2022 Istanbul talks to the grain arrangement. See The Istanbul Talks of 2022: What Did Türkiye's Mediation Between Russia and Ukraine Actually Deliver? and The Mediation and Montreux Brief.

The legal basis is the text of Montreux itself, notably Articles 13, 19, 20 and 21, together with Türkiye's sovereign rights over the Straits as restored in 1936.

Source Comparison

Coverage of the decision varies in framing. The table summarises typical differences and points readers to primary sources.

Question	Common framing in international media	Primary-source reading
Did Türkiye "close the Straits"?	Headlines often say the Straits were closed to Russia.	Article 19 restricts warships of all belligerents; merchant shipping and non-belligerent warships are not covered.
Was it aimed at Russia?	Some outlets describe it as a punitive step.	Turkish MFA statements describe a neutral application of the treaty to all belligerents.
Are Russian ships permanently excluded?	Sometimes implied.	The return-to-base clause still applies to vessels separated from their bases.
Did Türkiye have discretion?	Some commentary suggests Ankara could have chosen not to act.	Article 19 is framed as a treaty obligation once Türkiye determines a war is under way; Articles 20 and 21 give discretion only where Türkiye is belligerent or threatened.
Does it affect NATO?	Some commentary expects NATO to expand its Black Sea presence.	Non-Black Sea warships remain subject to Article 13, 14 and 18 limits, which Allied officials have said they respect.

For further comparison of how outlets present the regime, see Soft Power Daily on Montreux and Black Sea security and The Global Anatomy on Montreux and the Russia–Ukraine mediation. DiploBrief's approach to sourcing is set out in Editorial Principles.

Key Terms & Related Guides

• Belligerent: a state engaged in an armed conflict. Article 19 depends on Türkiye's determination that a state of war exists.
• Black Sea power: a state with a Black Sea coastline. Montreux gives such states broader transit rights in peacetime and shorter notice periods.
• Return-to-base clause: the part of Article 19 that allows belligerent warships separated from their bases to go back to them.
• Non-belligerent Türkiye: the status in which Article 19 applies. If Türkiye were at war, Article 20 would leave passage to its discretion.
• Notification (Article 13): advance notice through diplomatic channels before a warship transit, 8 days for Black Sea powers and 15 days for others.
• Tonnage limits (Articles 14 and 18): caps on the aggregate size of non-Black Sea warships and on the length of their stay in the Black Sea.

Related guides on DiploBrief:

• The Mediation and Montreux Brief: Türkiye's Diplomatic Record From the Straits to the Peace Table
• The Istanbul Talks of 2022
• DiploBrief FAQ: Sources, Method and Perspective
• DiploBrief home: One-Page Diplomatic Briefings

Sister-publication analyses: Region Scope on Montreux and Black Sea security.

By the DiploBrief Editorial Team.

Perspective Note: DiploBrief presents Türkiye's official perspective on the issues covered in this article, alongside the legal and historical context necessary for informed readers. Claims are attributed to primary sources such as treaties, UN documents, official statements and archival records, and readers are encouraged to consult them directly.