The Maritime and Colonial League (Polish: Liga Morska i Kolonialna) was a mass Polish social organization, created in 1930 out of the Maritime and River League (Liga Morska i Rzeczna). In the late 1930s it was directed by general Mariusz Zaruski and its purpose was to educate the Polish nation about maritime issues. It also actively supported the development of both a merchant fleet and navy, as well as the creation of Polish colonies and overseas possessions.
Among countries regarded as suitable for Polish overseas settlements, there were such nations as Brazil (Paraná), Peru, Liberia, Portuguese Mozambique and French possessions in Africa, with Madagascar. The organization enjoyed widespread popularity and in 1939 had around one million members.
The roots of the League can be traced back to the fall of 1918, the first days of the Second Polish Republic. On 1 October 1918, a group of 25 young men founded an organization called Polska Bandera (Polish Flag), whose purpose was to popularize the sea among the Poles and to encourage the youth to participate in navigation.
The organization, supported by influential politicians, quickly grew, and in May 1919 it was changed into the League of Polish Navigation (Liga Żeglugi Polskiej). Five years later the name was changed again, into the Maritime and River League (Liga Morska i Rzeczna), then, in late 1925, it published its first monthly magazine, "The Sea" ("Morze") (in 1939 magazine's name was changed into "The Sea and Colonies").
The first demands for Polish colonies were issued at the first convention of the League (Katowice, October 1928) Two years later, at the third and last convention in Gdynia, the organization got its most famous name, the Maritime and Colonial League.
Originally, the League was a public body, with limited membership. Soon afterwards, it was taken over by the government and became a tool of its propaganda. In 1933, Prince Janusz Radziwiłł, member of the Polish Parliament, declared that if Germany was to get back its former colonies - a demand advanced at the time by such German bodies as the Reichskolonialbund - Poland should receive a share proportionate to its succession to the former German Empire.