Water-mediated claims in both international law and domestic law are often framed around, or adjudicated based on land-centred principles. In Canada, too, such claims tend to be judicially assessed through land-centric concepts. This approach has significant implications for Indigenous law and related claims to water-mediated spaces. It also has consequences for both international law and domestic law, particularly with respect to how aqua nullius and similar Eurocentric concepts are disguised and used in settler-colonial states like Canada. Accordingly, this article urges a critical engagement with Indigenous law and similar cosmologies on water in a manner that foregrounds the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) and in re-reading how the UNDRIP is incorporated and implemented in Canada.