 Finland joined the League of Nations in 1920 , from which it sought security guarantees , but Finland 's primary goal was cooperation with the Scandinavian countries . The Finnish and Swedish militaries engaged in wide @-@ ranging cooperation , but were more focused on the exchange of information and defence planning for the Åland islands than on military exercises , or the stockpiling and deployment of materiel . Nevertheless , the government of Sweden carefully avoided committing itself to Finnish foreign policy . Another Finnish military policy was the top secret military cooperation between Finland and Estonia . 
