There is a growing awareness that both adaptation and mitigation measures are needed to reduce the impacts of climate change. Historically, due to a wide variety of reasons, mitigation and adaptation have been framed by scientists and policy makers as two different approaches to deal with the same problem: climate change. As a result, there are large differences in the way knowledge is produced, the analytical approaches that are used, and the designed policy strategies. This paper discusses the origin of the adaptation–mitigation dichotomy. Second, the paper addresses the relationship between climate change responses and spatial planning since there is a growing awareness that spatial planning can function as a switchboard for mitigation, adaptation and sustainable development objectives. Furthermore, the paper explores the role that spatial planning can play in developing effective mitigation and adaptation options in an integrated manner, searching for synergies and trade-offs. This creates the necessity to take climate change responses into account in spatial planning practices. We argue that climate change could also lead to changes in the traditional administrative structures that spatial planners are accustomed to. Since many of the main impacts of climate change have a water dimension, we discuss the river basin approach as the new administrative level at which spatial planning can increase the effectiveness of adaptation and mitigation measures and integrate these into other sustainable development policies.