Programmes to encourage staff to move within public sector organizations have become increasingly widespread in recent decades. Yet, although there are some anecdotal accounts, the effects of such intra-organizational mobility remain largely unexplored. Building on insights from organization theory and social psychology, we argue that intra-organizational mobility entails an important trade-off: it undermines movers’ depth of work-related contacts within the (new) department, while it increases the breadth of their work-related contacts outside it. Our empirical analysis evaluates this trade-off using a two-way fixed effects model for a longitudinal dataset of movers (N=149) and stayers (N=473) across two survey waves among European Commission officials in 2014 and 2018. Our main findings confirm that intra-organizational mobility is connected in opposing ways to employees’ intra- and extra-departmental work-related contact patterns. In line with theoretical expectations, we find these relationships to be stronger for employees who have previously experienced intra-organizational moves (‘repeat-movers’).