In this paper, we study the employment of workers from Central, Eastern and Southeastern European (CESEE) EU Member States in Austria after the Eastern enlargement of the European Union. To prevent a sudden rush of immigrants into the labor market, Austria opted for a Transition period during which immigration remained restricted. We will show that these restrictions had the anticipated effect; while the stock of workers from the new CESEE Member States increased slowly in Austria during the transition period, the trend became markedly steeper after the introduction of free labor market access. Between 2003 and 2016, the stock of workers from CESEE EU Member States in Austria increased fourfold by about 185,000 individuals. The largest immigrant groups are from Hungary, Romania and Poland. A large share of migrant workers are employed in seasonal industries and in border regions closest to their home countries.