The pilot study Internationally Mobile was conducted in 2014 by the Federal Institute for Population Research (BiB) in Wiesbaden, the Research Unit at the Expert Council of German Foundations on Integration and Migration (SVR) in Berlin and the University of Duisburg-Essen. For the first time, German emigrants and returnees were interviewed regarding their migration motives as well as their current and past living arrangements. The target population was selected on the basis of population registers from selected major cities in Germany. The random sample includes a total of 1,700 respondents, made up of 800 emigrants and 900 returnees. The technical report presents the design and implementation of the study on international mobility. Alongside the research design and the sampling method, the report documents the instrument and mode of data collection as well as the experiences in the field. Based on a comparison of the sampling frame with official statistics, the technical report presents analyses on data quality and the principal feasibility of the research design.