This paper investigates what information water resource managers think they need to make decisions on climate change adaptation. This is achieved through a hypothetical case study where participants, all actual water resource managers or in research, practitioner or administration roles linked to Australian water resources management, were given theoretical future climate scenarios and asked to make decisions based on the available information. The case study provided useful insights into why there is little evidence of effective climate change adaptation being implemented despite significant advances in climate impacts and adaptation science over the last decade. It was found that in order to bridge the gap between climate change adaptation recommendations and successful implementation at practitioner level there is a demand for: improved translation, communication and packaging of existing climate science information into sector- and location-specific impacts (e.g. hydrological interpretation of climate model rainfall projections and the associated uncertainties); attribution of historical and future hydroclimatic changes (e.g. not just what has happened or is going to happen but why and the confidence and likelihoods surrounding that); quantification of costs and benefits of any decision; and understanding of the social, political, and environmental contexts and level of acceptance associated with any decision.