Tourists have mostly directed their trips towards the sea, so it is not surprising that maritime tourism accounts for the majority of all tourist traffic in the world. Nautical tourism represents one of the most attractive forms of tourism in the Republic of Croatia, with a distinct potential for further growth. In this dissertation, according to the time criterion (length of stay in ports and marinas), the users of nautical tourism ports are observed through two categories: classic yachtsmen, who have their vessels and mostly use an annual or multi-month mooring in a marina or on dry land and stay in ports and marinas for four days or longer, and transit (passing) yachtsmen, that are in nature non-stationary yachtsmen who visit the coast, while they use nautical marinas for supplies and personal needs, and stay in ports and marinas for up to three days. By skillfully managing the determinants that affect competitiveness, the “art of managing” also becomes a factor that affects the competitiveness of nautical tourism. To manage the determinants of competitiveness in the best possible way, it is necessary to have an insight into all available resources and the characteristics of the target market. Therefore, to be able to talk about managing the competitiveness of nautical tourism by focusing on transit yachtsmen, it is necessary to specify the characteristics of this, so far, unexplored profile of guests. The essential part of this dissertation and the aim of the research is to show a higher degree of satisfaction with the offer and services of transit yachtsmen compared to classic yachtsmen, and additionally to determine the socio-demographic characteristics of a new segment that has not been described in the literature (transit yachtsmen) and to determine the characteristics of their stay, to better manage and increase the competitiveness of nautical tourism. The contribution of the dissertation is manifested in the fact that, for the first time in the Republic of Croatia, research has been conducted that looks at nautical tourism from the perspective of competitiveness observed through transit yachtsmen and investigates (theoretically and empirically) concrete components that affect the aforementionedX competitiveness. The empirical part of the work relies on quantitative research, more precisely survey research. The conducted research indicated the existence of a general level of satisfaction with the elements of the offer and the possibility of improving the quality of the elements of the offer. It also pointed to a new segment of boaters - transit yachtsmen, whose habits, wishes, experiences, and desires have not been covered by any research so far. The results of the research can serve practice because they provide specific characteristics of transit yachtsmen and their level of satisfaction and perception of the nautical tourism offer, bearing in mind their specific nautical needs. Likewise, the results can be used in further research related to specific forms of tourism and in the development of a strategy for improving the competitive position of Croatian nautical tourism - the dissertation indicated the current state of nautical tourism in Croatia, its neuralgic points, but also opportunities to improve its competitive position on the market. Certain limitations of the research are imposed, such as the relevance of the sample regarding the representation of categories of respondents (annual mooring users, monthly mooring users, and daily mooring users). The fact that the research was conducted in ACI marinas represents a limitation of the research, but the very importance of ACI marinas for the nautical tourism of Croatia and the for the researched topic indicates the possibility of concluding the population of transit yachtsmen. Furthermore, the short period of conducting the research (summer season) and the limited availability of respondents constitute a certain limitation of the research. The dissertation consists of introductory considerations and four parts, a concluding consideration, a list of literature, graphs, pictures and tables, and appendices. The first part of is entitled "The concept of nautical tourism as a selective form of tourism". The second part is entitled "Nautical tourism in Croatia". The next part of the dissertation is entitled "Competitiveness in tourism", followed by "Empirical research on the competitiveness of nautical tourism in Croatia", after which the last part of the dissertation is "Concluding considerations".