Inter-annual thaw subsidence is an important metric for monitoring permafrost degradation. We quantified thaw subsidence on the Brøgger peninsula, northwestern Svalbard, in a two-fold approach: differencing of high-resolution digital elevation models (DEMs) from 1936, 1995, 2008, and 2020, and calculating subsidence rates between 2019 and 2023 based on Global Navigation Satellite System (GNSS) positions. Our results reveal a long-standing subsidence trend across the Brøgger peninsula, with rates of -2.7 to -4.6 cm/year in DEM-based and -0.7 cm/year in GNSS-based analyses, showing higher subsidence in the 20th century than in recent years. Maximum subsidence occurred in a tundra fen area and was relatively large in topographic depressions and low elevations. This study is the first to demonstrate extensive thaw subsidence across the Brøgger peninsula, indicating widespread ground ice loss - a process notoriously difficult to detect. Thaw subsidence is a crucial yet often underestimated component of permafrost landscapes in the warming Arctic.