Over the past decades, tourism in the Kingdom of Saudi Arabia has been predominantly religious, diplomatic, or business-related. Recently, in the last quarter of 2019, as part of the Saudi Vision 2030, the Kingdom opened its market to the travel sector by launching the “Tourist Visa” for the first time. This new visa type produced a significant change by highlighting the importance of cultural tourism as the main key drive for development. Different tangible and intangible cultural heritage sites and assets have been safeguarded to support and enhance the new national tourism notion through heritage conservation projects and initiatives by governmental and non-governmental entities. This study investigates the balance between heritage conservation and tourism development in terms of sustainability, with particular attention to social, environmental, and economic aspects. This research aims to define the evolution of the conceptualization of heritage management before and after the country’s opening to tourism, paying attention to the balance between heritage conservation and tourism development in terms of sustainability, with particular attention to social, environmental, and economic aspects. The methodology used is based on a critical analysis of sustainable tourism development from the perspective of cultural heritage conservation via using a UNESCO-listed cultural heritage site, the Old City of Jeddah, “Historic Jeddah or Al Balad” as a case study. The results show that opening to tourism has profoundly changed the city of Jeddah, offering opportunities and risks. The originality of the research lies in the analysis of a fine geographical space that could have been more interested in cultural tourism during the past but has become competitive and sustainable in a short time frame.