Around the world, Indigenous people are preparing for futures of climate uncertainty and resource shortages. Indigenous communities are looking to the past and seeking guidance from their traditions – diverse systems of knowledge that change over time – so that they and future generations might nurture connections to the “deep time” of geological and human histories. In this essay we examine how the Wangan and Jagalingou Family Council in Australia and the Agua Caliente Band of Cahuilla Indians in the United States have taken long-term views on ecological sustainability and sovereignty. We focus on these two Indigenous communities on opposite sides of the Pacific Ocean because they are among the highest-profile battles over ancient groundwater in the past decade. Set against a backdrop of global settler state interference and exploitative economic practices, both cases reveal how the concept of kinscapes – or a shared sense of relatedness to interconnected ecosystems, histories, and places (or nodes) of belonging – can sharpen our understanding of environmental stewardship and its importance to Indigenous sovereignty. Whereas mining corporations and settler governments continue to make decisions with short- to medium-term objectives in mind, Wangan and Jagalingou and Agua Caliente leaders have used legal battles over groundwater to underscore their spiritual and physical connectedness with local environments. Like Indigenous communities around the world, the Wangan and Jagalingou Family Council and the Agua Caliente Band of Cahuilla Indians are making ontological choices by asserting their sovereignty through environmental stewardship.