Abstract: This article presents an analysis of recent developments in labor-related mobility (cross-border commuting) in the Danish–German border region of Sønderjylland-Schleswig. The region had an integrated labor market, until today's German–Danish border was drawn in 1920, dividing the historic Duchy of Schleswig. Until Denmark joined the EC in 1973, the Danish–German border was practically closed to labor-related mobility. Since then, commuting remained at very low levels until the mid-2000s, even though unemployment figures north and south of the border developed unevenly, and two national minorities had strong social and cultural ties across the border. From about 2005–2008 there was a drastic increase in commuting from Germany to Denmark, while commuting in the other direction has remained at a very low level. Here, the article comes up with some explanations for this development using the concept of (Un)Familiarity as developed by Bas Spierings and Martin van der Velde.