Cities worldwide are faced with the challenge of adapting to the effects of climate change as well as acting against climate change, in order to keep the urban area liveable in the future. To facilitate climate adaptation and mitigation on a national level, the Netherlands drew up guidelines to induce the energy transition, as part of the ‘Climate Agreement’, and to guide urban areas to adapt to the effects of climate change, as part of the ‘Deltaplan of Spatial Adaptation’. Both the energy transition and climate adaptation require context-specific solutions and place large spatial claims on cities. To create understanding on what the effects of the energy transition are on the possibilities for climate adaptation, in this research an explorative case-study is conducted, based on multiple and diverse cases in Rotterdam. Rotterdam’s main climate adaptation goal with regard to water resilience is to make the water-storing capacity of public space sufficient to prevent damage in the event of heavy rainfall (70 mm of rainfall within one hour). In order to find an answer to the question of what the energy transition entails for this goal, five pilot areas in Rotterdam that switch to a gas-free network in the coming years were taken as study sites and were thoroughly analysed to select cases. Cases have been selected based on their criticality: locations that are prone to urban flooding, in addition to the implementation of energy measures. For each of the five selected cases, cross-sectional designs were created for three situations: the existing situation, the situation with energy measures (and sewer replacement, if applicable) and the situation with climate adaptation measures. These designs formed the basis to empirically gather information on the different types of systems integration (project-based, geographical, physical and informational) between the energy transition and climate adaptation. By analysing five different cases in Rotterdam, concrete examples have been collected of how the implementation and planning of energy measures affect climate adaptation and of what the energy transition ultimately entails for Rotterdam’s climate adaptation goals. In addition, policy dilemmas have been formulated for the municipality with regard to the rainwater storage to be achieved and the extra costs associated with measures. This research indicates the difficulties associated with implementing both the energy transition and climate adaptation in densely built areas and tries to provide suggestions for exploiting potential opportunities that the energy transition can create for climate adaptation.