Bringing together 11 indigenous groups, Forum Musyawarah Masyarakat Adat Taman Nasional Kayan Mentarang (FoMMA) advocates for the rights of communities who live on 20,000 square kilometers of customary land in Northern Kalimantan. A large portion of their ancestral lands, mainly made up of forests and rivers, overlaps with Kayan Mentarang National Park. The park was the first in Indonesia to be placed under a collaborative management arrangement. Government and indigenous authorities, represented by FoMMA, decide jointly on resource management as well as traditional access and use rights, promoting local stewardship over the park. FoMMA has supported communities to document and map over 20,000 square kilometers of indigenous territories. In 2019, they secured legal recognition for a first block of 2,500 square kilometers of customary lands under national law. FoMMA’s communities pursue traditional forest-based local economies, and protect large swaths of rainforest in an effort to mitigate climate change and retain traditional ways of life.