Large landslides are prominent geomorphic features on many arid tablelands, yet their absolute ages and links to paleoenvironmental conditions remain poorly constrained. This study investigates landslides along the volcanic plateaus adjacent to the Sarmiento Basin in eastern Patagonia, occupied by Lakes Musters and Colh & uacute;e Huapi, an area characterized by significant Late Quaternary lake-level fluctuations. The region hosts extensive rotational and flow-type landslides, including some of the largest documented in Patagonia, with lengths exceeding 16 km. Using geomorphic mapping, luminescence dating of paleoshorelines, cosmogenic Cl-36 exposure dating of landslide scarps and deposits, and DInSAR analysis of recent ground deformation, we reconstruct a prolonged history of slope failures spanning >3Ma to the Holocene. We provide the first absolute age constraints for paleolake Sarmiento, revealing highstands during the Last Glacial Maximum (LGM) and Early to Middle Holocene. The most recent major phase of landsliding occurred after the younger lake highstand, suggesting that Early to Middle Holocene flooding of the basin-likely linked to capture of the R & iacute;o Senguer-together with wetter climatic conditions, may have triggered renewed slope instability. Pre-Holocene landslide ages remain less well constrained. However, failures from high mesas disconnected from modern lake shores yield significantly older exposure ages (>= 10(5) yr) compared to landslides along recent lake margins and valleys (similar to 10(4) yr). We propose that episodic wetter conditions and lake-level rises driven by enhanced Andean runoff or drainage reorganizations, periodically increased pore pressures in escarpments. This promoted slope failure within a landscape that has remained largely arid since at least the Pliocene.