The Pacific region presents some of the lowest water and sanitation coverage figures globally, with some countries showing stagnating or even declining access to improved water and sanitation. In addition, Pacific Island Countries (PICs) are among the most vulnerable countries on the globe to extreme and variable climatic events and sea-level rise caused by climate change. By exploring the state of water and sanitation coverage in PICs and projected climatic variations, we add to the growing case for conserving water, sanitation and hygiene (WASH) interventions within a holistic integrated water resource management (IWRM) framework. PICs face unique challenges of increasing variability in rainfall (leading to drought and flooding), increasing temperatures, and likely higher than average sea-level rise, all of which impact on freshwater security. Add to this geographic and economic isolation, and limited human and physical resources, and the challenge of WASH provision increases dramatically. In this setting, there is a stronger case than ever for adopting a holistic systems understanding, as promoted by IWRM frameworks, to WASH interventions so that they consider past and current challenges as well as future scenarios.