This paper investigates the causal effect of geographic mobility on income. The returns to German East-West migration and commuting are estimated, exploiting the structure of centrally planned economies and a "natural experiment" of German reunification for identification. I find that the migration premium is insignificantly different from zero, the returns for commuters equal to 40 per cent, and the local average treatment effects for compliers are insignificant. In addition, estimation results suggest no positive self-selection on unobservables for migrants, and some evidence of positive self-selection on unobservables for commuters.