Indicators are increasingly recognized and used as instruments for the exploration, planning, monitoring and evaluation of policy measures. They also help to bridge the gap between policy, science, and the wider public. In the Scheldt estuary, different administrative levels, authorities and the private and public sector operate on both sides of the border (Flanders-Netherlands) and coherent spatial planning is necessary. A set of indicators of sustainable development (ISD) can be used in this context for: Monitoring of policy relevant processes in space and time Evaluation of policy plans, Indicating temporal and spatial aspects of policy information Providing transparent and objective scientific information to target groups (policy and management, scientists, the wider public) Supporting an integrated management of the Scheldt estuary Visualizing and weighing of sectoral priorities A coherent set of ISD is not yet available for the Scheldt estuary. Building on existing data and ISD for other regions, this project aims to develop a set of ISD, aligned with the current long-term vision of the Scheldt estuary. Therefore the study area needs to be defined and a database built to support the indicators. Cooperation between Flemish and Dutch parties will be essential. An instrument needs to be developed to make the indicators available for end users. The data consultation needs to be interactive. The indicators will be available via the ScheldeMonitor website.