Estuarine and coastal ecosystems are essential for human activities, as they provide a wide variety of ecosystem services (ES). However, they are subject to increasing anthropogenic pressures incurred by coastal development, marine traffic, overexploitation of aquatic resources and diversification of tourism and recreational use. Accounting for these human-ecosystems interactions in land planning projects, in a comprehensive, holistic and integrated way, is still a challenge in decision-making. The “Cost to coast” research project aims at filling in the existing gaps in this integration and providing the missing elements that prevent the sustainable development of coastal/estuary territories, by using life cycle assessment (LCA) methodology and tools. “Cost to coast” project is divided into four inter-related research activities that will allow reaching four objectives. First, it aims at proposing a harmonized conceptual framework for the consistent assessment of ES at a territorial scale throughout a life cycle perspective. Second, it will develop a methodology to identify the “basket” of ES relevant to estuarine and coastal areas, which are shared by different stakeholders at a territorial scale (e.g. maritime freight and port activities, fishing, recreational-tourism, high value conservation area), by applying the conceptual framework initially developed. Third, it will create a new set of indicators to be applied in quantitative life cycle impact assessment methods (e.g. readily available to LCA practitioners for use within IMPACT World+), in order to quantify the potential loss/gain of aquatic ES (i.e. from coastal and sea use), in compliance with the conceptual framework developed. Finally, this project aims at applying the developed methodologies and set of indicators to characterize the human impacts on ES. The operationalization will be conducted on two case studies, i.e. the Thau lagoon, on the Mediterranean Sea coast, in France; and the St. Lawrence estuary, in Quebec (Canada) with a specific focus on the Lac Saint-Pierre. These two territories have different sets of ES, though the direct provision of resources with the presence of aquaculture, fishing and shellfish farming activities; as well as indirectly, through cultural services, such as those linked with recreation and cultural activities. The project is scheduled for 3 years and it combines the expertise of six different research teams from Québec and France, as an evidence of its multi- and inter-disciplinary character. The researchers and graduate students are involved in various fields of research and development, such as LCA (system analysis, impact assessment methodology development, LCA operationalization), ES quantification and valuation, marine ecology and biology, geography and economics. The project will deliver high qualification staff (4 PhD, 1 Postdoc and 3 MSc students), scientific papers and communications. Lastly, the “Cost to coast” project pays attention to serving and better informing the decision-making process. For that, tools, documentation, and other project deliverables will be made available to territorial stakeholders and to the lay public, in simple wording and, at the same time, to the LCA community (i.e., practitioners and researchers) in order to ease and sustain its use.