This background paper offers for the first time a comparative analysis of the 28 overseas entities of the European Union; its purpose is to establish the current state of existing knowledge on the impacts of climate change on the biodiversity of the European Union overseas entities. It starts with a thematic analysis presenting the transversal threats on overseas entities in the face of climate change. Subsequent sections, specific for each of the 28 entities, provide some contextual data and an overview of their remarkable biodiversity, in addition to presenting the new threats resulting from climate change. Lastly, examples of responses to climate change or “best practices” are reported for selected territories.