Coastal Management aims to promote sustainable development of coastal zones. Increasing pressures in coastal areas, but also ICZM policy requirements (e.g. Agenda 21, SDGs) have resulted in efforts to develop indicator sets to measure the state and progress towards sustainability in coastal areas. Indicators are considered to provide a simplified view on complex phenomena, quantify information and make it comparable, and facilitate communication and are used within European environmental policies to describe the present and future state of the environment. Thus, indicators are regarded as important tools in European coastal and marine policy and have been used for many years to monitor the EU Sustainable Development Strategy. In order to assess the degree and success of ICZM implementation in the EU, a working group on indicators and data (WG-ID) was set up, and developed two sets of indicators: 1) an indicator set to measure the progress of implementation of ICZM (progress indicators) and 2) a set of indicators to measure sustainable development of the coastal zone (sustainability indicators), which covered environmental, social and economic aspects. Subsequently, both sets were tested within several European projects (e.g. DEDUCE, CoPraNet, COREPOINT).

Since then numerous indicator sets to assess coastal sustainability have been developed on local, regional, national, European and global scale. Within the project SUSTAIN an indicator-based method to measures sustainability on a local level was developed in cooperation with coastal communities. It consists of an indicator application in which municipalities can conduct a self-assessment of their state of sustainability. In a second step, the sustainability pillars (environmental quality, economics, social well-being and governance) and supporting issues (e.g. air pollution, sustainable mobility) are weighted in a facilitated weighting exercise based on their importance. This promotes a discussion and exchange between stakeholders, which can be used to develop a vision for future development and raises awareness about sustainability issues. Furthermore, combining both steps helps to adjust the indicator set to local situation. Yet, in general acceptance on a local and regional level remained low. Reasons for this include lacking expertise, limited access to data, time and resource constraints, low relevance and lack of immediate and concrete benefits for coastal communities.

Besides assessing sustainability and progress of ICZM implementation on different spatial levels, indicators can also be applied to concrete case studies in order to assess the success of measures. Hereby, they can be used to evaluate whether a measure leads or led to progress towards sustainability and to what extent the process followed the principles of ICZM and steps of the ICZM cycle. As such they can be applied during different steps of the ICZM cycle or the SAF, for instance during the System Assessment to evaluate different management options with respect to their implications on sustainability, or during the Monitoring & Evaluation step to assess, whether the measure and its planning and implementation process was successful.