Currently, mitigation and adaptation measures are considered as two different approaches due to differences between the two actions and segregated practices and policy. However, there is a growing interest that synergetic approaches to adaptation and mitigation in an integrated way can bring substantial benefits at multiple sectors, while reducing the impacts of climate change. Nonetheless, efforts to promote synergies between adaptation and mitigation measures are rare and mostly limited to theoretical and conceptual level. There is limited knowledge on how it can be planned and designed in a spatial-explicit manner. Thus, this thesis fills in the knowledge gap by exploring the potential role of a seascape approach for the synergetic integration of climate actions. There is a growing awareness that spatial planning and design such as a landscape approach can function as a framework by integrating mitigation and adaptation with other socio-economic desires to promote multiple benefits. Given the increasing importance of marine environment in times of climate change, this thesis explores a seascape approach based on a systems thinking to a landscape approach. In this thesis marine environment can be understood as the new spatial realm at which spatial planning and design can increase the effectiveness of adaptation and mitigation measures while integrating them with careful consideration of marine ecology. This is illustrated with a propositional concept of artificial islands in the Holland coast.