In November-December 2018, GMIT was contracted by the Marine Institue (via Public Tender) to conduct a desk study on Irish Marine non-indigenous and invasive species. This is a requirement driven by international obligations to monitor the status and risks associated with invasive species, as indicated by a range of EU directives and regulations. Peer-review and grey literature was searched for the compilation of this initial list, which should be updated on a regular basis in order to satisfy certain criteria and fulfil descriptors of EU regulations.