The 21st century rivalry of the maritime powers took the form of substitute activities. These are military incidents, control, or seizure of a shipping entity, and activities that threaten shipping itself. This determines the state of maritime security of Poland, because the Baltic has become one of the areas of its conduct. The adopted form of importing energy carriers along with the forming an alliance with the US construction of the alliance with the USA creates the possibility of taking hostile actions against it. It is necessary to adapt the form of operation of the Polish Navy to these threats. Based on the analysis of international, and national legal regulations, strategic documents of maritime powers, and applied forms of maritime activity, the scope of changes in Polish maritime policy was determined. Modifications of the definition of terms maritime piracy and unlawful assault at sea in Polish legal regulations were considered necessary, they should also include activities of maritime terrorism, subversion and sabotage of offshore facilities and installations, as well as ships operating. The principle of linking defense tasks against the sea attack, and maintaining navigation continuity was proposed as an element determining the construction method of the Polish Navy and the scope of combat training. On this basis, its combat potential and scope of training were determined. It should cover four areas (preparation for defense operations, combating nontraditional risks, how to respond to provocative, and criminal activities).