Finnish–Estonian defence cooperation

Practical co-operation began with the initiative of the Finnish general staff in February 1930 in Tallinn and the first joint war games were held in 1933.

There were defence plans involving Finland launching a massive assault against Leningrad if the Soviet Union started a war against both countries.

However, the plan would also have required the participation of Latvia, and according to the Finnish military leader, Carl Gustaf Emil Mannerheim, the countries would have needed outside help from the League of Nations.

[1] Practical measures by Finland and Estonia were based upon Peter the Great's Naval Fortress system, allowing surface ships and coastal artillery fire to prevent possible movements of the Soviet Baltic Fleet.

The defence co-operation aimed to prevent access by Soviet vessels through the Gulf to Helsinki and Tallinn using mines, coastal artillery fire and submarines.

[1] During the Winter War, Estonia was formally neutral, but it had to allow the Soviet Union to establish military bases and station troops on its soil.

During the Winter War, Estonian military staff gave the Finns top secret information on Soviet troop movements.

The Finnish Chief of the General Staff Lennart Oesch (left) monitors Estonian army military exercises in October 1938. The Estonian Chief of the General Staff, Nikolai Reek is second from the right.
President of Finland Pehr Evind Svinhufvud (left) and President of Estonia Konstantin Päts (middle) in the city of Narva in 1936. State visits were scheduled every year. The most important negotiating issue was military co-operation.
The Estonian submarines Kalev and Lembit were both manufactured in the United Kingdom and began their service in spring 1937.