The World Heritage Convention protects sites of universal natural and cultural values, sometimes in combination. In 2015, it was amended to incorporate references to the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP). International conventions are always in danger of becoming the hand-maidens of their signatory states. When evidence emerges that they have succumbed, it fuels criticism of cosmopolitanism. At the same time, environmental leaders sometimes clash with Indigenous people over efforts to conserve the natural values of traditional lands for the ‘global good’. This article asks how international instruments with cosmopolitan ambitions influence the discourse and practice of national and subnational environmentalists attempting to find common ground with Indigenous groups. Drawing on interviews with 25 Australian environmental leaders, it finds the World Heritage Convention and UNDRIP have encouraged a pragmatic cosmopolitan practice among environmentalists, despite continuing intercultural differences in some quarters.