In order to achieve and sustain destination competitiveness it is important and necessary to follow quantitative and qualitative trends. By adapting and following the trends, tourism supply is opening for new possibilities. The Island Mljet belongs to the group of Dubrovnik islands, and is second in the group measured by the size. It is a part of the Mediterranean climatic area, what is the reason why tourism is highly developed. Quantitative trends weren't generally changed, but because of the covid-19 pandemic, the situationhas changed.By analysing the Island's qualitative trends, visible changes were detected. They were caused by various components but primary by pandemic. Because of the possible system changes, which can be negative and on long term, it is primary to research the trends, and to respond on time. This research presents the qualitative and the quantitative tourism trends of the Island, and their positive and negative impactson tourism and sustainable development of the island. Passive vacation, increase in demand and service quality and sustainability neglecting are the reasons for the lack of development of special forms of tourism.Above mentioned has changed during the pandemic. By analysing the projects that were organised on the Island in order to achieve better sustainable tourism development, it will be concluded either changes are positive or negative. Positive trends can also affect tourism destination negatively. This study analyses specific types of tourism that already existed on the Island, and alsosuggests development of specific formswhich could improvethe quality of the tourism offerand ensure high level of sustainable tourism development. This study also presents how the trends and the business of the entrepreneurs onthe Island wereaffected by the pandemic.