This article uses curricular information from a sample of applicants to the Spanish Ramón y Cajal

programme to, on the one hand, assess the extent to which international mobility has an impact on

the collaboration patterns of researchers and, on the other hand, to address the connection between

collaboration patterns and the likelihood of return to Spain. We focus on two main types of collaborations:

co-publications and collaboration in research projects through formal participation. We find

that longer stays abroad seem to provide better opportunities to publish with a host principal investigator

and to participate in research projects in the recipient country. We find that the length of the

stay also has an impact on the likelihood of return to Spain: longer stays abroad reduce the likelihood

of return. However, a longer duration international stay does not affect the collaboration links maintained

with the home country, which may persist over time. We also find that public financial support

is crucial for explaining and facilitating the return of Spanish researchers from abroad.