The South Shetland Islands offer ice-free margins with periglacial surfaces that are only a few decades old after the recent glacier retreat. Ground-penetrating radar (GPR) profiling was used to g permafrost Occurrence as deduced from active layer advance. Local acquire information on young GPR measurements included grids of parallel single-offset 2D reflection profiles and multi-offset measurements to determine wave velocity in the ground. Excavations served to determine the sedimentary composition and to backup GPR profile interpretation. GPR results show that the active layer could easily be traced at a site 140 m above sea level (asl), which is placed in volcanic soil. In contrast, GPR data were ambiguous at a site low in altitude (35 m asl), where frozen and unfrozen ground was imaged next to each other and GPR interpretation relied on ground verification.