Antarctic ice-free inland sites provide a unique perspective on the strategies coevolving organisms have developed for survival at the limits of life. Here, we provide the first combined description of the ecological and genetic diversity of lichen photobionts colonising an isolated Antarctic inland site, Coal Nunatak, on south-east Alexander Island (Antarctic Peninsula). Photobionts of 14 lichen species (42 samples), all belonging to the group of coccal green algae, representing the entire lichen community of Coal Nunatak were investigated using the internal transcribed spacer region (ITS) of the nuclear ribosomal DNA. The study attempted to address the hypothesis that mycobiont selectivity for the photobiont partner is lower in more extreme environments. This hypothesis did not appear to hold true for the entire lichen community except one species. Another aspect focuses on the relevance of the reproduction modus concerning the distribution of photobiont haplotypes in the lichen community.