The distribution of the Critically Endangered Leadbeater’s possum (Gymnobelideus leadbeateri) is largely confined to a small area of the Victorian Central Highlands. This species relies on hollows in large old trees for denning and nesting. Tree hollows are usually only found in mountain ash trees over 120 years of age. However, most of the known distribution of Leadbeater’s possum is in forest that is 80 years of age or younger, and our understanding about how this animal uses and moves through young forest is limited. To address this knowledge gap, we designed a new harness and GPS tracker system that could safely track the nocturnal movements of Leadbeater’s possum. Our tracking research will continue for several years, and will provide new insights into how far Leadbeater’s possum colonies travel through forest of different ages. This information will be vital to ensuring the development of effective management strategies for the species.