This paper aims to evaluate the accuracy of official Bolivian foreign trade statistics. Results show large discrepancies between Bolivian records and those of its main trade partners during the First World War. Whereas the gap decreased thereafter, it stayed particularly high in the case of exports. This seems to be explained by mistakes in the geographical assignment by the trade partners rather than by an overvaluation of official Bolivian figures. This suggests that landlockness may have had a significant negative effect on the accuracy of trade statistics from the, a priori, more reliable countries. The study also helps to revisit the debate concerning the effect that tin exploitation had on the rest of the Bolivian economy during the first half of the 20th century.