The city of Benidorm is the most renowned mass tourism destination on the Spanish Mediterranean coast. It has been recently acknowledged as a sustainable urban development to support the mass-tourism industry; however, Benidorm had received strong criticism during many years, mainly because of its striking urban image. The aim of this paper is to showcase the relevant role of sustainable urban design for the development of an effective coastal tourism product. To this end, the specific conditions, facts, and regulations that have led to the current urban design of Benidorm city are presented; and, the key singular urban features of its urban plan contributing to the sustainability of this singular urban model are analyzed. The results suggest that the land occupation strategy, the design of outdoor spaces, and the diverse leisure and accommodation offer, have a favorable impact on the optimization of the city resources, creating a successful tourist destination.