The Declaration recognising the Right to a Flag of States having no Sea-coast (French: Déclaration portant reconnaissance du droit au pavillon des États 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 under its own flag.
As of 2013, the Declaration has been ratified by over 50 states, and international law recognises the right of any state to sail ships on the sea under its own flag. Today, land-locked states which have merchant vessel fleets include Austria, Azerbaijan, Bolivia, Ethiopia, Hungary, Laos, Luxembourg, Mongolia, Moldova, Paraguay, Slovakia and Switzerland, though of these, only Ethiopia and Mongolia have no river/sea port from which the high sea can be reached.
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 Germany 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 behavior of ships of bearing its flag because of the state's inability to unreservedly access ports and the sea. Prior to World War I, Switzerland had denied several requests from merchant ships to fly the Swiss flag.
After World War I, the creation of several new landlocked 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 landlocked states to transit goods and personnel across German territory freely to seaports, which suggested that such states may also have their own merchant vessels in such ports.
The Declaration was created to reflect the new consensus and 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.
The text of the Declaration states:
The undersigned, duly authorised for the purpose, declare that the States which they represent recognise the flag flown by the vessels of any State having no sea-coast which are registered at some one specified place situated in its territory; such place shall serve as the port of registry of such vessels.
Barcelona, April the 20th, 1921, done in a single copy of which the English and French texts shall be authentic.