The ecosystems formed by estuaries and coastal areas are essential for the maintenance and development of human activities by providing a mix of Ecosystem Services (ES). These ecosystems are under increasing anthropogenic pressures linked to the coexistence of multiple uses in limited spaces, with increasing urbanization, an increase in maritime transport, an overexploitation of aquatic resources, or the diversification of recreational and tourist activities. The tools available to support and guide decision‐making for sustainable management of these territories do not allow the impacts of human activities on ES to be properly integrated, in particular those that offer an integrated, holistic and coherent perspective, such as the Life Cycle Assessment (LCA). The Cost to Coast project aims to fill these gaps and develop the missing elements in order to be able to assess the sustainability of a coastal maritime development project at the territorial level, while avoiding the transfer of impacts, following a life cycle perspective. Cost to coast is organized around four interconnected research components, which will make it possible to: 1. create an integrated conceptual framework, based on a scientific state‐of‐the‐art, for the evaluation of ES, consistent with a territorial LCA perspective 2. develop a methodology to identify and assess the mix of ES, consistent with the biophysical properties of the coastal zones and the perceptions of stakeholders 3. develop indicators for life cycle impact assessment to assess the resulting positive and negative impacts (integrated into the IMPACT World + method) 4. apply the methodology and indicators developed in two case studies, in close interaction with stakeholders in the field, i.e., the Thau Lagoon in France, around the Mediterranean, and the estuary of the St. Lawrence River in Quebec , with an emphasis on Lake Saint‐Pierre.