There are different definitions of tourism in the world. Every man, tourist and visitor in many different ways identifies tourism with traveling or recreation. A tourist is every person which travels outside of the place of his permanent place of living to a tourist destination so that he can participate in tourist activities, but without doing any economic activity. Driving factors which are responsible for making decisions about travel are very important. At first, tourism in the world was connected with population migration, but the first touristic travels were bound to the Olympic Games. In Croatia, tourism started developing in the 1850. when the first hospices for foreigners were being opened. The appearance of selective types of tourism was noted in the 1970s, and some of the important characteristics are individual traveling and importance of activities at destinations. Nowadays, types of selective tourism are in constant development, and some of them are health tourism, religious, ecological, dark tourism and so on. Because of the massive numbers of tourists and the pollution of tourist destinations, sustainable development of tourism was introduced. Sustainable development is based on 4 main principles: ecological sustainability, social and cultural sustainability, economical sustainability and technological sustainability. Eco tourism is one of the types of selective tourism which takes place in protected areas. The tourists who participate in eco tourism are called eco tourists and they are divided in two groups: soft and hard eco tourists. The difference is passive participation of soft eco tourists in touristic activities and physical activity of hard eco tourists. Protected areas in Croatia include national parks, nature parks, strict reserves and so on. National park Plitvice Lakes is the oldest and most visited national park in Croatia. It consists of 16 intertwined lakes. The park is protected in 3 zones: strict protection, active protection and usage zone. Every zone has precisely determined activities in which tourists can participate in and measures with which tourists must comply.