Mediterranean coastlines are undergoing a strong process of urbanization due not only to demographic growth, but also to the development of tourism. Moreover, municipalities have become more dependent on residential tax income, which creates a vicious circle for local urban planning. The Var department, in south-eastern France, can be considered as a relevaznt example of these dynamics, where residential urban sprawl is threatening existing vacant lands. At the same time, most of these territories still have a high natural value and agricultural potential. In this paper, we describe our inventory of vacant lands on a large territory (two intermunicipalities, which include 24 municipalities) at parcel scale, to give an innovative assessment of this phenomenon. We investigated non-residential development possibilities for existing vacant lands through possible pathways for sustainable planning projects. In particular, the impacts of increases in agricultural spaces were explored in the normative scenarios and were measured through socio-economic indexes. This work shows that there is still a large amount of vacant land (23.5% and 37% respectively for the two case studies) with different opportunities for agricultural valorization. It had to be taken into account that these lands are often on the fringe of urban areas, where the urbanization process is stronger. The possible alternative scenarios suggested here can be used as examples for policy makers, to encourage a different point of view regarding land use planning.