In the 1970s and 1980s, North and South Yemen appeared to be two states pursuing opposing, sometimes hostile, economic and political policies. Then, in 1990, they suddenly united. This article analyses sport diplomacy as an instrument in opening institutional contacts between the two governments and as a venue for conveying important socio-political and historical messages. Cross-border football contests reinforced the largely invented notion of a single Yemen derived from pre-Islamic kingdoms. This idea remains a foundation of Yemeni nationalism and a base of Yemeni national identity.