We identify factors influencing young scientists' plans for research stays abroad by embedding theories of social inequality, educational decision making, and migration into a life course framework. We test the developed model of international academic mobility by calculating a structural equation model using data from an online survey of scientists employed at German universities below the rank of full professor. We find that earlier international mobility mobilises scientists to plan a research stay abroad. This turns out to be a potential channel of social inequality reproduction, as individuals from a high social origin in particular spend time abroad in their early life course. Moreover, scientists' research contexts play a vital role: Internationalised institutional environments and academic disciplines as well as personal international networks create opportunity structures that ease research stays abroad. Similarly, the current social context matters: Parenthood decreases the likelihood of plans for international mobility among female scientists. This may entail long-lasting gender inequalities. Finally, young scientists striving for an academic career are more likely to plan a research stay abroad than those with exit plans. Our results show that beyond the current context, both past life events and future life goals shape scientists' decisions about international mobility.