Tourism is a crucial source and an added value in many developing countries. In Morocco, the sector is of paramount significance with a national GDP of about 20% and its effects have become noticeable. The methodology which is used in this study is qualitative while the data is analyzed according to a process-based approach in two longitudinal periods, from 2001 to 2009 and from 2010 to 2014. Through a process-based longitudinal study, the effects of tourism were analyzed highlighting the three pillars of sustainability, namely the economic, environmental and socio-cultural milieu in Essaouira in the southwest of Morocco. The objective of this paper is to identify, among others, the notorious impacts of mass tourism on fragile destinations in terms of their load capacity, promotion of youth employment and respect for indigenous traditions. This study also aims to assess the influence of tourism on certain destinations that depend, to a large extent, on this activity. It also seeks to test a series of indicators germane to sustainable development in sensitive areas. Within results, it was found that tourism, as an industry, is related to the international community and the tested sustainable development indicators revealed that tourism is environmentally destructive. Job creators in this field contributed to the changes that occurred in the indigenous people's lives and the state's intervention was of paramount significance to preserve the existence of a potential vanishing culture.