Water managers around the world are facing challenges when trying to manage water resources sustainably, particularly when confronted with increasing water scarcity. This article examines four river basins in Africa, Asia and Australia, with wide-ranging histories, politics and hydrology, to consider some of the key common challenges faced in very differing hydroclimatic conditions and the approaches being taken in response. It is proposed that elements in common between these basins can provide knowledge for use in other situations. A comparison of these elements suggests that many basins face difficulties due to geopolitical situations and that problems meeting competing demands, particularly in the context of water scarcity, will be exacerbated by climate change. In response to these challenges and in moving to manage water resources sustainably, water managers should consider: co-operation, trust-building mechanisms and political will; stakeholder engagement; reliable data and monitoring; co-operative benefits; and flexibility between multiple uses in water allocations.