Sensitive Ecosystem Assessment and ROV Exploration of Reef (SeaRover), Synthesis Reportan extensive offshore reef survey of Ireland’s continental slope was commissioned by the Marine Institute in partnership with the National Parks and Wildlife Service (NPWS), funded by the European Maritime and Fisheries Fund (EMFF), and coordinated and led by INFOMAR (Integrated Mapping for the Sustainable Development of Ireland’s Marine Resources). The objectives of the survey were to implement the EMFF’s Marine Biodiversity Scheme - Natura Fisheries, by mapping offshore reef habitats with a view to protecting them from deterioration due to fishing pressures. The reef project aligns with sub-article 6.2 of the Habitats Directive (EC 92/43/EEC) which requires member states to take measures to avoid deterioration of protected habitats. The Sensitive Ecosystem Assessment and ROV Exploration of Reef (SeaRover) survey took place between 2017 to 2019. The 2017 and 2018 surveys took place onboard the ILV Granuaile whilst the third survey leg in 2019 employed the Marine Institute’s RV Celtic Explorer. The Marine Institute’s remotely operated vehicle (ROV) Holland I was used for each of these cruises. The Holland I was equipped with a high-definition (HD) camera, various composite video feeds and a robotic arm for sample collection. The primary aim of the survey was to map the distribution and abundance of biogenic and geogenic reef habitat along Ireland’s continental margin using HD video.