Although international mobility is associated with various positive outcomes, the process of knowledge transfer resulting from working abroad has not yet been sufficiently investigated. The main reason why the relationship between international mobility and knowledge transfer is still underresearched is that there are not yet reliable methods to identify knowledge transfer. The current study aims to close this research gap by introducing a network-based approach that is capable of indicating knowledge flows. Assuming that coauthorship constitutes one instance through which knowledge transfer can take place, the approach relies on coauthorship networks. In the first approach to be presented, the transfer of published knowledge is operationalized as the use of rarely cited publications. In the second approach, the transfer of methodological know-how is operationalized as the occurrence of lexical terms in abstracts of publications. The study focuses on German scientists who were internationally mobile and acted as knowledge transmitters between the country of mobility and Germany. The results show that the network-based approach is well suited to identifying the sources of knowledge, knowledge transmitters, and the recipients of knowledge. Moreover, the findings suggest that knowledge transfer processes are field specific.