EN
The activities of the Polish submarines during the September campaign is the subject of histo-rians’ researches practically since its completion. Reviewing the accumulated material, one can see that it contains, in the vast majority, of the detailed descriptions of the facts or events (reportage convention), and to a lesser extent, we are dealing with the trials of their fusion, rarely the evaluation of the accumulated material is done from the commanding and stuff point of view. Just the lack of such a "reflection" was the inspiration to take up the topic of this article. The article discusses the process for preparing the squadron to war, based on the avail-able documents, including not widely known "secret ballot envelope", which survived on ORP Wilk , which could be used to do planning work and made their assessment. Considered alternative possibilities for the solutions adopted and attempted to answer the question, why the only variant adopted was the defensive one. It illustrates, in a synthetic way, combat of the ships after the outbreak of the war after the cessation of hostilities on the coast. It also shows seldom raised in writing, and important in the planning of the operational activities of the ships, the problem of the knowledge of the Stockholm Declaration. Considerations have been enriched by the designed graphic material. The evaluation of plans of usage submarines squadron in the September campaign closes the considerations and shows their subsequent implementation at the operational and tactical level. The final proposal, although evaluates negatively the process of planning the use of submarines, indicates the high professionalism of their commanders and crews that were the main reasons for not scuttling them by the op-ponent naval forces.