One common idea within participation theory is the need for new approaches in decision making that emphasize a two-way interaction between decision makers and the public as well as deliberation among participants. Citizens should be given the opportunity to weigh evidence, discuss and debate potential decision options and possibly arrive at mutual agreements by which all parties can abide. The demand for sound scientific information and public participation is particularly great especially in adapting to some of the impacts of climate change such as floods due to sea level rise. The uncertainties and the socially sensitive nature of such risk, makes it important for all relevant stakeholders to be involved. This study draws on two research projects carried out in Sweden and Denmark with the intention of engaging stakeholders in finding suitable ways of adapting to climate change. The two cases that have been selected for this study include the SEAREG (Sea Level Change Affecting the Spatial Development in the Baltic Sea Region) and the BALTCICA (Climate Change: Impacts, Costs and Adaptation in the Baltic Sea Region). Using a comparative case study method, this thesis looks into the design of participatory processes and the conceptions that underlie them, as well as the consequences on the active participation of other stakeholders with a particular focus on the public. Some of the main differences on the extent of public participation between these projects are sorted out and compared using theoretical perspectives from participation theory. Both cases cut across the local and national scales of decision making and use flooding scenarios in communicating with the public. However, the design of these scenarios as well as the participatory models differ.