Northern Australia's marine ecosystems face complex challenges requiring innovative solutions for conservation and management. The region boasts globally significant seagrass habitats, crucial for their economic (fisheries, tourism), conservation (marine parks, threatened species), and cultural values (dugong, green turtle). Data on these important habitats suffered from historical fragmentation and inaccessibility. Addressing this, we compiled 40 years of survey data between Cape Arnhem (Northern Territory) and the southern Great Barrier Reef, covering 14 seagrass species, >130,000 geolocated sites and 1700 meadows. This historical data is now publicly available. The process highlighted significant knowledge gaps, which are being addressed through modelling seagrass species distributions, using remote sensing data to map and hindcast seagrass condition, compiling historical data from adjacent regions, and building collaborations between researchers, Traditional Owners, rangers and government to conduct on-ground mapping, including in marine parks and Indigenous Protected Areas. This work underscores the importance of detailed spatial data for informed decision-making, with data already used in fish survey design, blue carbon mapping, dugong distribution modelling, healthy country planning and assessing the effectiveness of spatial management. It also provides a foundation for predicting how seagrass species and the animals that depend on seagrass will respond to future disturbances and environmental change.