Most of the literature on property markets is written as though it were the very paradigm of a neoclassical perfect market. Land speculation is an intrinsic characteristic of land markets, but it is often omitted in economic approaches of market efficiency and is rarely placed in its geographical context. In this paper, we explore the spatial, economic and financial dimensions of land speculation effects on market efficiency within an institutional and social economics economic perspective, by considering planning regulations, land tenure system, and land transactions, within the geographical context of a tourist agglomeration development in Greece. Within the context of increasing demand for means of accommodation, bank financing practices and state subsidy systems favoured the creation of new enterprises, the accommodation supply and consequently the increase in land demand. Land property structures, urban planning regulations and state policies have d etermined land supply. All the above factors have produced synergies that encouraged land speculation with ambivalent effects on local real estate markets, tourist activities and space, thus creating conditions of market inefficiency.