A well-developed understanding of natural mortality, movement and space use, and their drivers are critical for the implementation of effective species conservation and habitat management. Acoustic telemetry is an effective tool for monitoring individuals over time. Long-term data can then be used to investigate movement patterns in response to environmental conditions and can provide long-term mark-recapture data for identifying mortality. The river sharks (family Carcharhinidae, genus Glyphis) of northern Australia comprise two rare and threatened euryhaline species. A total of 197 Northern River Sharks (Glyphis garricki) and Speartooth Sharks (G. glyphis) were tagged with acoustic transmitters and tracked in rivers of the Northern Territory’s Van Diemen Gulf between 2013 and 2024. Detections from 185 sharks were converted into capture histories and used to calculate yearly and monthly estimates of mortality. Data demonstrate that river sharks experience high rates of mortality, particularly in younger individuals. Glyphis glyphis and G. garricki neonates experienced average yearly mortality rates of 0.898 and 0.731, respectively, compared with 0.120 and 0.233 in subadults/adults. Movements of tracked G. garricki and G. glyphis demonstrate seasonal migrations up- and downstream which are closely linked to freshwater flow. During the dry season, sharks occur on average ~50 –120 km upstream and move downstream to the river mouths and inshore coastal waters during the wet season. Results demonstrate that river sharks have very limited capacity to withstand additional anthropogenic causes of mortality such as incidental capture in fisheries. Movements indicate that river sharks sustain increased risk of mortality from fisheries seasonally. Further, movements are strongly linked to environmental variables indicating that the species are also highly sensitive to environmental change. Developments which alter flow, water quality, and availability and quality of habitat have the potential to cause declines in river sharks due to their small populations and low dispersal and connectivity. Insights into mortality and movements of G. glyphis and G. garricki in the Northern Territory can inform management and help to ensure that river sharks persist into the future in a changing world.