We characterized the diversity, distribution, systematic colonization, and xerophilic capabilities of fungi associated with the Antarctic angiosperms Colobanthus quitensis and Deschampsia antarctica collected at different sites of the South Shetlands Islands, Antarctic Peninsula. A total of 684 fungal isolates were obtained and identified into 67 taxa from 32 genera. The highest fungal diversity and richness were obtained from the rhizosphere, roots, and leaves, in order, and only 11 taxa shared between both plants. Penicillium and Pseudogymnoascus were the dominant fungal genera. However, the rarefaction curves for plant fungal assemblages did not reach a plateau, suggesting that these Antarctic plants may host more fungi in their tissues and rhizospheres. A total of 460 isolates grew at water activity (aw) = 0.95, 200 at 0.90, 110 at 0.81, and 47 at 0.66. Antarctomyces, Cladosporium, Mortierella, Leptosphaeria, Penicillium, Pseudogymnoascus, and Thelebolus taxa grew at aw = 0.81 and 0.66 and considered highly xerophilic. In addition, specific isolates of Penicillium and Thelebolus exhibited the highest mycelial growth at aw = 0.66. Our results show that the internal tissues and rhizosphere of Antarctic angiosperms host rich and diverse fungal communities dominated by cold-adapted and endemic taxa, which seem to coexist as symbionts and decomposer fungi. In addition, specific fungi are able to colonize different parts of the plant, suggesting a high ecological relationship with their hosts. Finally, different fungi living in the rhizosphere displayed remarkable xerophilic tolerance, representing promising candidates for further biotechnological studies, including identification of genes for applications in industry and agriculture.