The Erasmus Impact Study ―Effects of Mobility on the skills and employability of students and the internationalisation of Higher Education Institutions is designed to fill these gaps with regard to the effects of such mobility on both individuals and HEIs. The study is based on a mixed-methods approach to research, merging large-scale quantitative surveys with qualitative surveys of various target groups and control groups of mobile and non-mobile individuals. Empirical, perceptional and attitudinal items were combined to explore the effects of Erasmus mobility and IPs. The study also explores the differences in individual and institutional achievements through the Erasmus programme across the eligible countries.