The article examines the role of German submarine warfare in the context of strategies and tactics of the First World War. The key aspects are considered, including the goals and consequences of the economic blockade organized by Great Britain, and the response actions of the German fleet. Special attention is paid to the influence of unrestricted submarine warfare on neutral powers, which became one of the factors of the US entry into the war. The article analyzes the pace of U.S. naval construction, the large-scale development of the convoy system and anti-submarine defense, which ensured the successful transfer of American troops to Europe. The article provides statistical data on the number of ships sunk and their tonnage, the dynamics of losses in maritime communications, as well as on changes in the effectiveness of German submarines under the influence of anti-submarine measures of the Allies. The diplomatic steps of the United States, which led to the cessation of the submarine war by Germany and the signing of an armistice, are particularly highlighted. Based on the work of researchers based on archival data from the period under study, the author analyzes the consequences of submarine warfare for the outcome of the World War, including the transfer of German submarines to the Allies and the completion of naval operations.