Laser ablation–inductively coupled plasma–quadrupole mass spectrometry analysis on hydrothermal cassiterite was applied to solve the long-standing debate on the age of the central European Erzgebirge-Krušné hory tin province of eastern Germany and the western Czech Republic. Cassiterite samples from the Sadisdorf, Ehrenfriedersdorf, Altenberg, Cinovec-Zinnwald, and Krupka tin deposits have U-Pb ages that overlap within the 2σ uncertainty range, and define a relatively narrow time window of 326 ± 3 to 320 ± 3 Ma. These dates also define the minimum age of the associated highly evolved alkali feldspar granite intrusions, which so far could not be reliably dated by conventional U-Pb, Sm-Nd, Rb-Sr, or 40Ar-39Ar techniques due to high-U metamict zircons and resetting by later thermal events. The time span of ca. 326–320 Ma characterizes the age range of regional rare-metal granite magmatism and associated hydrothermal tin mineralization in the Erzgebirge as a result of extensional collapse of the Variscan orogen.