Declaration recognising the Right to a Flag of States having no Sea-coast

The Declaration recognising the Right to a Flag of States having no Sea-coast (French: Déclaration portant reconnaissance du droit au pavillon des Etats dépourvus de littoral) is a 1921 multilateral treaty which legally recognised that a land-locked state could be a maritime flag state; that is, that a land-locked state could register ships and sail them on the sea using its own flag.

In the first two decades of the 20th century, there had been uncertainty as to whether a land-locked state could register maritime ships and authorise them to sail under its flag: France, the United Kingdom, and Prussia had argued that such a right could not exist because it would place a land-locked state in the position of being unable to control the behaviour of ships of bearing its flag because of the state's inability to unreservedly access ports and the sea. Prior to the war, Switzerland had denied several requests from merchant ships to fly the Swiss flag.

After the First World War, the creation of several new land-locked states—such as Czechoslovakia, Austria, and Hungary—caused the great powers to reconsider the issue. The Treaty of Versailles had included provisions by which Germany agreed to allow these land-locked states to freely transit goods and personnel through German territory to sea ports, which suggested that such states may also have their own merchant vessels in such ports. The Declaration was created to reflect the new consensus. The Declaration was concluded and signed on 20 April 1921 by 25 states in Barcelona, Spain, at the League of Nations Conference on Communications and Transit as an addendum to the longer Barcelona Convention and Statute on the Regime of Navigable Waterways of International Concern, which was concluded on the same day. The Declaration entered into force on 8 October 1921.

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