Once abundant throughout Moreton Bay Marine Park (MBMP), subtidal oyster reefs are now considered functionally extinct due to anthropogenic pressure from coastal activities (e.g., pollution, overharvesting and disease). Despite their ecological significance as habitat engineers and water quality regulators, and likely upcoming listing on the EPBC List, the distribution of remnant subtidal oyster reefs is currently completely undocumented. In this study, we mapped and characterized remnant subtidal oyster reefs across select areas of MBMP. Areas of investigation included a 10km section of the Pumicestone Passage, which were established through visual surveys using satellite imagery. We created high-resolution (~1m) Digital Bathymetry Models across the focal areas using sonar data collected with an acoustic sounder. Terrain metrics gathered from these models were then used in combination with measures of benthic composition, obtained through underwater drop-camera surveys, to establish the condition and extent of reef structures. The next phase of the project will establish relationships between the location of reef structures with landscape connectivity and composition variables (e.g., distance to intertidal reefs). Understanding the distribution of subtidal oyster reefs is critical for informing conservation strategies, restoration potential and guiding efforts to re-establish lost foundational habitats.