Crustose coralline algae are a highly numerous and morphologically diverse group of ecologically important habitat-forming red seaweeds. They support a high diversity of organisms and play a role in blue carbon but are vulnerable to environmental impacts including rising sea temperatures and ocean acidification. The Falkland Islands, which remained unglaciated in the Last Glacial Maximum, are pivotal for marine diversity in the South Atlantic and indeed the Southern Ocean. This archipelago lies in a vast area of ocean with other isolated islands and distant land masses influenced by polar currents, making the region a biogeographic laboratory. It supports a rich seaweed flora including many crustose coralline algae, most of which are undescribed. This project provides a unique opportunity to i) document coralline algal diversity using novel genomic approaches, ii) undertake an in-depth study of species ecology/distribution, iii) explore holobiomes of specific species, and iv) study the Falkland Islands’ results in relation to global phylogenies, and by exploring historical and contemporary collections data from around the world.