Nautical tourism is a phenomenon which has recorded in the last three decades one of the most developed rate well-known in European and Croatian economy. Economic predictors of tourism development agree that nautical tourism is at the initial developing period and the valuable developed results are only to be expected. The development of nautical tourism from the scientific print of view has not been sufficiently presented in touristic science. Nautical tourism means a new economic developing chance for Croatia and that has stimulated ever growing, vivid, scientific and research activity in Croatia and on the Mediterranean. To understand better what we can expect from nautical tourism, first of all, it is necessary to define it. Nautical tourism, being a multi-functional activity, is possible to be investigated and defined in multi-disciplinary way. It is necessary to confront and add some new forms of defining and classification to already existing, definition and classification of nautical tourism developed at the School of Humanistic Science – Zadar. In this respect nautical tourism is defined with some practical and scientific aspects but the simplest definition is nautical tourism is a multi-functional touristic activity with a very emphasized nautical component. A practical division of nautical tourism is based on several sources, legislative, statistical which is added by National classification activity. In that way the basic classification of nautical tourism has been imposed: 1. Ports of nautical tourism 2. Charter 3. Cruising Within this division the practice has been shown other sub-divisions which are necessary to be investigated and classified. Why is this classification practical and logical? What is the point to scientific definition of nautical tourism from practical aspect? Does the practical classification of nautical tourism negate classification of the School of Humanistic Science? Why is nautical tourism defined and classified. All these questions have been answered here in detail.