Bycatch, the incidental capture of non-target species in fishing gear, has been recognised as the most significant global conservation threat affecting seabird species. Geographically, bycatch rates vary widely, depending on local fishing efforts, environmental features, and seabird community composition. Regional and local research is essential due to the complexity of accurately extrapolating general conclusions regarding the impacts of bycatch. Existing European bycatch research predominantly focuses on northern regions, leaving a significant knowledge gap regarding bycatch in the Mediterranean Sea. This work presents findings of wintering diving seabirds as bycatch of small-scale fisheries in a coastal area of the northern Adriatic Sea, based on data collected between 2021 and 2023. Seabird distribution varied along the depth profile. The bathymetric range between 3 m and 5 m was the most exploited by fishermen. Bycatch of seabirds was confirmed in the study area, with five species recorded, i.e. Black-necked Grebe Podiceps nigricollis, Red-throated Loon Gavia stellata, Black-throated Loon Gavia arctica, Mediterranean Shag Gulosus aristotelis desmarestii, and Great Crested Grebe Podiceps cristatus. Our results suggest that bathymetry likely plays a strong influence on bycatch occurrence. Incidental captures were not widespread but appeared concentrated in the shallowest depths <5 m and the range <2.5 m was identified as particularly susceptible due to the low associated fishing effort and the majority of bycatch events recorded. We estimate that between 46 and 108 birds were incidentally captured during the research period. This study identifies key factors shaping the areas of bycatch vulnerability and risk, proposing a spatial–temporal mitigation framework within Natura 2000 sites and highlighting the value of local stakeholders’ engagement.