Coastal zones are submitted to pressures, due to population growth and continuous expansion of human activities, which become more intense by the effects of climate change. These pressures lead coastal administrators and stakeholders into taking actions to protect and further develop the coastal zones. Those actions are not always within the framework of spatial plans. Land-Sea interaction is an important factor that should be taken into account during the implementation of Spatial Plans. To this end, assuring the coherence between coastal terrestrial and marine planning is a prerequisite, as the coastal zone is the link between marine and terrestrial space. This paper aims to identify the land and sea uses interactions that result from a series of projects. As case study, the wider area of Heraklion, Crete Island, is considered. In Heraklion area, a series of projects in coastal zone are proposed to be implemented, by different stakeholders operating in the area. The methodology follows, a holistic decision making procedure that include the analysis of alternatives, categorisation and quantification of the consequences and implementation of trade-offs, aiming to introduce a method to assess the interactions between future land and sea uses, identify the land and sea uses interactions by quantifying the consequences of each intervention.