Automatic Identification System (AIS) has to be on board in every ship over 500 gross tonnages (GT) in Japan from July 1, 2008. This is a response of??amendment of maritime relating laws in accordance with SOLAS (International Convention for the Safety of Life at Sea) Convention and IMO (International Maritime Organization) requires all ships over 500 GT or upward are fitted with ship borne AIS.??AIS is a system which makes it possible to get precise on-line information from a large area about ships and their movements. AIS is based on a ship borne radio wave of VHF, it continuously and automatically transmits fixed, dynamic and voyage-related information and receives corresponding information from other ships near by.??VTS (Vessel Transport Service) is provided by collection of AIS information from ships. Most of the VTS stations around the area of Gulf of Finland have equipped with coastal surveillance system with radar for early warnings to endangering ships.??????Combinations of AIS and VTS, in addition, practical lane-separation system have also been activated under international agreement of Russia, Estonia and Finland. These three systems are well combined and??organised then significant effects of reducing risks of ship borne accidents have been observed. Practices of Gulf of Finland should be introduced other congested sea lanes.