The issue of free passage through territorial waters has been the subject of both doctrinal and practical interest for many years. One agreement concerning this issue is STRANG 1100 - Principles for NATO naval vessel visits to NATO and non-NATO ports. This agreement came into force for NATO member states in 1995. STRANG divides visits into official, informal, and working categories. The official visit is one that occurs upon invitation by one of the parties or is connected to an important state or international celebration, provided that the second party agrees to categorize the visit as official. The informal visit is a friendly visit in the port of one of the parties and is not concerned with any official celebrations. The working visit takes place during NATO maneuvers, during which navy vessels require repairs, supplies, and the transport of people, fuel, and other materials.In addition to the principles described above, STRANG regulates certain issues of protocol, issues concerned with the agreement coming into force and obligations imposed by its provisions, restrictions to the agreement and the information forms which are addressed to the country hosting the visit.The author also discusses the Polish rules that are significant in light of the topic addressed.