Youth activists around the world are demanding urgent climate action from elected leaders. The annual United Nations climate change negotiations, known as COPs, are key sites of global organizing and hope for a comprehensive approach to climate policy. Drawing on participant observation and in-depth interviews at COP25 in 2019, this research examines youth climate activists’ priorities, frustrations and hopes for creating just climate policy. Youth are disillusioned with the COP process and highlight a variety of ways through which the COP perpetuates colonial power structures that marginalize Indigenous peoples and others fighting for justice. This is intersectional exclusion – the character of exclusion experienced by people with multiple intersecting marginalized identities. We demonstrate that the space, policies and even the social movement organizing at COP25 are exclusive, necessitating new ways of negotiating, building relationships, and imagining climate solutions that centre Indigenous communities, and protect and return to them the lands on which they depend. As the youth climate justice movement grows, attending to Indigenous priorities will help it transform, rather than reinforce, the systems at the root of climate crisis and to challenge existing policymaking structures.