This chapter discusses the anti-fascist campaigns orchestrated by the International of Seamen and Harbour Workers (ISH) in Northern Europe during the 1930s. The organisation was a short-lived transnational radical coordinating umbrella body for communist-dominated/controlled trade unions of maritime transport workers established in 1930 during the ‘Third Period’ of the Communist International. The chapter explores the establishment of anti-war committees in Scandinavian harbours during the Manchurian Crisis in 1931–1932; the intensification of agitation and propaganda work of the Interclubs in the Scandinavian countries among German seamen. It highlights the intertwined relationship between local and national campaigns launched by the ISH and its sections in the Scandinavian countries and Comintern policies on a global level. Communist agitation and propaganda among the maritime transport workers was initially organised through the International Propaganda Committee of Transport Workers. There had been a vision of an umbrella organisation for radical maritime labour unions, that is a Red International of Water Transport Workers’ Unions.