The present study examines the effects that a 3-week study-abroad (SA) experience and a set of individual differences have on the foreign language (FL) development of a group of 64 Catalan/Spanish speakers, learners of English as an FL. Moreover, the present study attempts to account for the outcome differences between successful and less successful FL learners. Results suggest that short SA experiences are beneficial for the FL development, that certain individual differences such as motivation and FL use in free time (among others) play a role, and that the successful and less successful learners' SA experience differed in several aspects that could explain the differences in their outcome.