The giant dragonfly, Petalura gigantea, is an endangered species and serves as an umbrella species for the conservation of upland swamp habitats in south-east Australia. Its long-lived fossorial larvae rely on high water tables within these upland swamps. Traditional surveys for P. gigantea involve walking line transects during the flying season, from October to February. To enhance these survey methods, we developed an environmental DNA (eDNA) assay to detect P. gigantea in upland swamp discharges. The eDNA assay successfully detected a known population and indicated the presence of larval populations in two swamps where traditional surveys had not identified the species. Using swamp water balance models, we demonstrated that while eDNA sampling shows promise, consideration of basic climatic data and the likely hydrological status of the swamp(s) to be sampled is essential to improve detection probability. This presentation details the eDNA method, which is recommended to be used in tandem with traditional survey techniques. The combined approach will aid in the conservation of P. gigantea and, by treating it as an umbrella species, support the groundwater-dependent communities in Australia’s upland peat swamps.