The formation of the Tibetan Plateau involved the opening and closing of multiple oceans (the ‘Tethyan’ oceans) and the rifting, drifting and collision of multiple continental terranes, but quantitative paleogeographic constraints on the motions of these tectonic ‘puzzle pieces’ are scarce. Here we present paleomagnetic data from one of the central pieces of this puzzle—the South Qiangtang terrane—which allow us to determine that it was located at a latitude of ~22°S in middle Permian time, 265 million years ago. This paleolatitude constraint further allows us to estimate the width of the Tethyan oceans on either side of the South Qiangtang terrane in the middle Permian, providing a first-order snapshot of the evolving paleogeographic puzzle that gave rise to the Tibetan Plateau.