Bio-geogenic rocky outcrops in the northern Adriatic Sea, locally known as "tegnùe" or "trezze", are highly valuable habitats and biodiversity hotspots. This study presents the application of underwater Structure-from-Motion (SfM) photogrammetry for the mapping and characterization of these habitats. The investigated areas include three biogenic outcrops located near Caorle (Venice), including the Natura 2000 site “Tegnùe di Porto Falconera”. These sites are situated at various distances from the coast, at depths ranging between 6 and 20 meters, and are characterized by different size, morphology, and ecological conditions. Surveys were conducted between 2022 and 2026 by CNR scuba divers using a multi-camera rig and specific protocols tailored for the low-visibility conditions typical of these environments. High-resolution (submillimeter) orthomosaics and Digital Elevation Models were produced and analyzed through digital image segmentation and taxonomic identification at the highest possible resolution. Morphometric analyses and ecological metrics based on megabenthic cover were computed. This approach enabled a high-resolution, spatially explicit biological and ecological characterization of the outcrops. Furthermore, the generated datasets were analyzed using indicators and indices for ecosystem status assessment, calibrated against traditional photo-quadrat methods. This step aimed to validate the SfM approach for bioindication and biomonitoring, establishing it as an effective tool for the conservation and management of these vulnerable habitats. Moreover, this framework provides a methodological basis for long-term monitoring and restoration initiatives of these habitats and their associated biodiversity.