This study describes and discusses the marine casualties, the effectiveness of existing traffic services, and marine safety and Vessel Traffic Service(VTS) in Korean coastal waters. Marine traffic is comprehensively assessed in Korean waters, an analysis of casualties is undertaken by block scheme. Marine environmental parameters are identified relating to marine casualties as appropriate. Various statistical techniques are employed to evaluate the inter-relationships between individual causal factors, and for the first time effect level is instituted to quantify the relative importance of the causal factors in Korean waters. A further innovation is the examination of the adequacy of existing Korean traffic services by casualty and traffic analysis, and an accident danger index is introduced to compare accident danger over different .time periods. A mixed population of contributors to marine safety is sought by questionnaire. The design of this is both innovative and original in content in order to evaluate the perceived importance of the various risk factors, the marginal effectiveness of various options in reducing risks, and their weight with regard to YTS services and activities, the main part of the study uses an original multiple coefficient to estimate casualty reduction rate and a new method to quantify the effectiveness of VTS. The Korean waters traffic study is conducted as an intermediate level and provides the data base for the main body of work. The conclusions include recommendations with respect to the stricter enforcement of the routeing scheme(TSS) and the adoption of further traffic observation/surveillance over the areas concerned. Finally it is noted in particular that additional Vessel Traffic Service and Traffic Separation Schemes are now required if any substantial improvement is to be achieved in marine traffic safety in Korean coastal waters.