One of the most important concepts concerning the safety of navigation is the ship domain. The maritime domain is one of the oldest domains, which preceded the ones used in aviation, railway industry, chemical industry and medical. Through the concept of a ship domain is to be understood a certain area around the vessel, which the navigator wants to keep free of other fixed and moving objects. Navigational situation can be considered safe as long as no other ship neither any navigational obstacle would not exceed the area. In order to build and develop methods to assess the safety of the navigation, a ship probabilistic domains for three types of vessel encounter situations were determined based on the AIS traffic monitoring data. The aim of the paper is to present a method to identify navigational incidents on the basis of a probabilistic domain, which can be used to assess the safety of navigation and discovery places potentially dangerous for navigation in the selected areas of the Baltic Sea.