\n This dataset originates from a standardized benthic survey conducted in 2017 at multiple coastal locations around São Miguel Island, Azores (Northeast Atlantic), within the scope of the ASPAZOR project. The primary objective of the sampling campaign was to characterize the composition and spatial variability of shallow subtidal macroalgal assemblages across representative benthic habitats of the island. Using consistent field methodologies, the survey generated a robust baseline of macroalgal community data, enabling comparisons among sites and supporting assessments of benthic biodiversity patterns at local and regional scales. The dataset provides reference information relevant for ecological assessment and long-term monitoring, including the evaluation of environmental variability, human pressures, and potential changes in community structure over time, such as those associated with the introduction or spread of non-indigenous species in coastal ecosystems. This dataset is made publicly available under the BenthicAZ project (recipient of the DTO-BioFlow second Open Call), aimed at contributing to the consolidation, standardization, and open dissemination of coastal benthic biodiversity information from the Azores, supporting future research, monitoring programs, and regional data integration efforts.\n