Post-accession migration from Central and Eastern Europe (hereinafter CEE) is unique in that it grew in many cases to become massive and spontaneous in a very short period after the European Union (EU) enlargement of 1 May 2004. Membership of the EU for CEE countries created a crucial momentum for social change in terms of migration processes from those countries. Although migration had taken place before, in the 1990s and earlier, there was an elimination of restrictions in access to selected labour markets. Patterns of migration have since been changing mostly in terms of substance and scale, but also in terms of structure, affecting both the countries seen as sending and the receiving countries.

Any explanation of post-accession migration patterns, trends and mechanisms must first get to grips with the complexities of this phenomenon. Migration from CEE countries can be said to fall into a number of epochs based on specific historical events and influenced by policy changes. In the past twenty years or so, mainly since the collapse of communist regimes and the opening up of these economies, migration and mobility of individuals from CEE can generally be said to move from a period of largely illegal migration and specific, limited options for labour mobility to a period of ‘free mobility’. Earlier mobility was associated with certain sectors or seasonal work and favoured specific nationalities, for example, through bilateral agreements in the 1990s and early 2000s. However, after EU enlargement, first in 2004 and then in 2007, nationals of these CEE member states had more access to live and work in other countries within the EU. Within a maximum of seven years of their EU membership, all restrictions on their access to other EU countries were to be lifted.

The period of transition in the mid-1990s until 2004 saw increasing outflows, albeit with limits in terms of the scope of opportunities. According to the World Bank (2007: 10), only a few countries among the EU-10 had experienced sizeable migration to Western Europe before their membership of the EU (these were Poland, Romania and Bulgaria). Bilateral agreements were of particular importance. The largest bilateral agreement was implemented in Germany beginning in 1991, and Polish temporary workers were the main beneficiaries.