The main factors determining the threats to Ukraine’s national security from the maritime direction in the part concerning the underwater space within the territorial sea of Ukraine are: increase of naval forces and their armament by other countries of the Black Sea region; presence of territorial claims; unresolved issues regarding the borders of economic maritime zones and the distribution of the continental shelf; economic interests of Ukraine and encroachment on its natural resources; conducting intelligence activities in national waters; terrorism at sea. Comprehensive consideration of threats to the national security of Ukraine provides for the definition of each threat as large as possible its characteristics, which are subject to assessment (measurement) in quantitative or qualitative form. The threat description obtained in this way will be the so-called «Threat Passport». The threat passport is a document in which various data are entered, which comprehensively characterize this or that threat to national security in order to achieve the most complete picture of it. The description of threats to Ukraine’s national security from the maritime direction is proposed to be carried out according to the following characteristics: the formation of the threat (real, potential). Potential threats are understood as such threats, the probability of their practical realization of which is low in the medium term, and real threats are those that already have examples of manifestation, and the probability of their actions is quite high in real time; the nature of the consequences (threat to the vital interests of the state, threat to the important interests of the state, threat to the peripheral interests of the state); scale of consequences (significant, moderate, insignificant, small); sources of origin (international relations, environmental problems, man-made problems); threat orientation (political sphere, military security, state border security, economic sphere, ecological sphere, information sphere); location (external, internal); form of manifestation (overt, covert); types of possible measures to counter the threat (political, diplomatic, economic, legal, military, information and psychological); required types of resources to counter (internal, external). The main tool for comprehensive consideration of threats to Ukraine’s national security from the maritime direction in peacetime in the part concerning the underwater space within the territorial sea of Ukraine is the monitoring of the underwater situation. Keywords: anti-ship defense, grouping of ships, naval forces.