A867 Sustainable port development and integrated coastal management (ICM) require: (i) ecosystem-based or integrated design, (ii) a future orientation, (iii) stakeholder-inclusive processes. Stakeholder-inclusive processes, the focus of this paper, increase the diversity of knowledge and the availability of information, and expand the pool of creativity in a development initiative. As such, they address the bounded rationality of a single actor or group of actors with limited information on their coastal (port) system and limited ability to explore and process all potential options for such a system. Stakeholder participation is also considered ‘good governance’, and forms an inherent component of ICM. In this paper we investigate the added value of stakeholder-inclusive processes conducted in the scoping phases of several coastal and port projects in data-poor environments. We evaluate 5 cases: Sustainable port development in Tema (Ghana), ICM in Sao Tome, ICM in Guinee for the island of Kaback, for Grand Bassam (Ivory Coast),and Richards Bay/ Mhlatuze in terms of 7 categories of added value, namely: 1. Data collection/ Ground-truthing: biogeophysical and social aspects 2. System understanding: governance, social and biogeophysical aspects 3. Insight in past and current actions/ strategies 4. Eliciting problem perceptions, values and priorities 5. Developing new solutions/ Creativity: changing scale, issues involved, future visions 6. Process design preferences: who should be involved, how and when 7. Increased support for new coastal and port development strategies. Overall, we determine that although scoping was the primary focus of the cases, the participatory processes contributed to generating potential solution options, and preparing for evaluation and decision making. The range of potential solution options broadened– more issues were identified, and the fit with the local needs improved. The added value of the participatory process is clarified further by comparing with earlier non-participatory initiatives in some of the case studies. Then, the implemented ‘solutions’ came as a surprise to the local community as stakeholders were not engaged, nor informed about the measures that were implemented. Finally, the lessons learned from the case studies regarding the added value of stakeholder inclusive approaches within the scoping phase of ICZM and seaport development projects are linked explicitly to data poor situations. In particular, we find indications that data gathering and ground-truthing and developing a shared system understanding and insights on the effects of past and present actions, are particularly valuable.@en