The Farasan Archipelago in Saudi Arabia is an Important Plant Area (IPA) in the Arabian Peninsula. This paper describes the flora of the Farasan Islands and provides an up-to-date botanical checklist together with background information on the geology and fauna of the islands. It designates the locality as an IPA due to the presence of nationally and regionally rare species and the presence of good examples of mangrove vegetation, which is both regionally and globally threatened. In addition to conservation assessments, this study also examines conservation planning concerns, particularly the colonisation of the main island Farasan Al-Kabir by the invasive species Prosopis juliflora. Suggestions for conservation action are provided. A new combination is made for Tetraena boulosii.