Since its foundation the transnational experiment called the European Union (EU) has tried to provide a political form for the ancient idea of Europe. This has been attempted by establishing a set of rules opposing the entropy of the international system and setting up a common market, therefore continuing the process of political integration sanctioned by treaties. These rules have generated a dense network, which has grown up, surprisingly, beyond all proportions, entangling “goods and persons” and at times delaying the overall growth of the system. The geopolitical space of the EU has expanded or decreased because of historical social factors and the political willingness, or not, of the ruling coalitions of its member states. In more than 40 years of its recent history, Europe has been a divided entity reproducing variables of political thought and socio-economic systems in contrast one with the other: East and West, a planned economy against the free market, totalitarianism and democracy. The collapse of the Soviet paradigm in 1991 and the ensuing gradual reunification of the European continent have not only forever altered a vision of the world, but they have also sparked movements of populations long appeased, thus making migration regimes and the impermeability of European borders subjects for discussion. The idea proposed in this paper is the need to look at the transformations of the EU migration space in the period that starts in the 1980s, goes through the 1990s, until the decisive appointment of 1 May 2004, the day that sanctioned the fifth and more imposing EU enlargement. The last date is actually a starting point for the continent to look further and try to identify the empirical form and political features within today’s migration scenario in the enlarged EU.