This report summarises the results of the project "Measuring Learning Mobility in Vocational Education and Training" (specific contract n° VC/2019/0024 signed between Directorate-General for Employment, Social Affairs and Inclusion, Unit E3 and GOPA, under the Eurostat framework contract 2018.0086). The current project has aimed at supporting DG EMPL Unit E3 - VET, Apprenticeships and Adult Learning in exploring ways to improve data availability on learning mobility in Vocational Education and Training (VET). The current project has implemented an expert survey to identify and evaluate the potential data sources. The project looked into available national approaches for observing Initial Vocational Education and Training (IVET) learning mobility, mainly based on a review of the available literature and on qualitative expert interviews. This report comprises of six main sections and four annexes. After the introduction, section 2 provides a summary on the background and the goals of the project. Section 3 gives an overview on the options for and challenges of measuring IVET learning mobility across the EU 28 Member States (MS). In section 4 the overall research strategy of this project is outlined. Section 5 introduces the methods applied for the expert survey and summarises the results of four expert interviews and of the expert survey, constructed by key approaches for measuring IVET learning mobility. Section 6 presents the conclusions with regard to the future measurement of IVET learning mobility and proposes a new proxy indicator on IVET learning mobility based on Erasmus+ data.