Post-collisional potassic volcanic rocks on the Tibetan Plateau are widespread, but geologically young (<375 ka) volcanism suitable for ²³⁸U-²³⁰Th geochronology is rare on the plateau. The geologically young Ashikule volcanic field from northern Tibet offers an excellent opportunity for studying high-resolution timescales of magmatism in continental collision zones. Here we report U-Th crystallization ages of zircons from Ashishan volcano and Wulukeshan volcano within the Ashikule volcanic field. In this study, we have identified 3 pulses of zircon crystallization at circa 70 ka, 105 ka, and 290 ka for Ashishan volcanic rocks and 1 pulse of zircon crystallization at circa 115 ka for Wulukeshan. Comparison of high-resolution zircon crystallization ages of 70 ka and 105 ka with respective eruption ages indicate that the zircon crystal residence time for the Ashishan volcano is short (<5 kyr). The presence of 290-ka zircon in a different Ashishan lava flow suggests the 270-ka volcanic pulse previously reported for other volcanoes in Ashikule volcanic field also occurred at Ashishan. The zircon crystallization age of ~115 ka for Wulukeshan volcano suggests that Wulukeshan volcano erupted later than previously inferred. Similar zircon age spectrums of ~105–115 ka for Ashishan and Wulukeshan volcanoes suggest a common interconnected subsurface magma reservoir for these two young volcanoes during Pleistocene time. Our new high-resolution U-Th zircon age data reveal that post-collisional potassic magmas below northern Tibet erupted soon after their formation (<5 kyr), in spite of their passage through thick continental crust. The high abundance (~60%) of geologically old (>375 ka) zircons demands for crystal-scale isotope studies of the widespread post-collisional lavas in continental collision zones, as the complexities cannot be resolved by bulk analysis methods alone.