In this article, we put forward a conceptual map for understanding the role ecocentric narratives can play in future Integrated Water Resources Management (IWRM). By comparing Western and Indigenous scholars' narratives of river governance, we show how this makes two different ontological narratives of the river possible. By using liminality and the rite-of-passage narrative of the learning journey associated with it, and by understanding how different river governance narratives rely on different ontological scaffolding, policymakers can gain a better understanding of alternative approaches to river governance that synthesise Western and Indigenous insights. The paper makes two contributions. First, we extend the debate of integration beyond its current centre of gravity around an anthropocentric perspective to show how an ecocentric vantage point open new understandings of IWRM. Second, we consider the river as a stakeholder in its own right and explore how ecocentric narratives and knowledge can lead to an improved role for ecosystems and Indigenous stakeholder engagement in IWRM policy design and implementation. We look at the case of Whanganui River in New Zealand - a river that was granted legal personhood in 2017 - in order to reflect on the limitations and opportunities of implementing an ecocentric approach to IWRM in practice.