The victory of the Soviet Union in the Great Patriotic War came at a high price. During the fighting, the USSR Navy lost 50.3% of its submarines and emerged from the war weakened, especially in terms of submarines, the construction of which required a significant investment of time and material resources. In these conditions, the use of captured submarines opened up certain prospects for quickly replenishing combat losses, but they played a minor role in strengthening the USSR Navy. This book includes submarines that were part of the Navy of the Union of Soviet Socialist Republics before World War II , captured by Soviet troops from Estonia and Latvia, captured from Romania and Germany as trophies during the fighting during the Great Patriotic War and received as reparations from Germany and Italy at the end of hostilities. The book also includes foreign submarines raised from the bottom of the sea and subsequently included in the USSR Navy. In preparing the book, documents and materials from the Central Naval Archive, the Central State Archive of the Navy, and the Central State Archive of the Soviet Army were used , archive of the Research Historical Group of the Navy, Central Archive of the Ministry of the Navy, personal library of the author.