This contribution examines the various international instruments, in both hard and soft law, that have been established by international organisations such as the WTO and WCO and scrutinises how they have been implemented into EU legislation governing the EU Customs Union, thus demonstrating the substantial influence of international instruments on the Customs Union. As the relevant international instruments affect not only the traditional elements of European customs law, but also the EU’s entire export control regime and the framework of the internal market, this contribution demonstrates, moreover, how the Customs Union functions in a globalised world.