The present study explored whether two semester overseas study programs had any impact on participants' language ability and motivation to study English. The language ability, L2 learning motivation and learning attitude of 65 Japanese university students participating in semester-long study abroad programs were measured pre departure and on their return. TOEIC listening and reading tests were used to measure students' linguistic gains, and possible changes to students' L2 motivation and attitudes were measured using a survey created specifically for the purpose of this study. Statistical analysis implied a significant effect from the two overseas programs on TOEIC scores and motivation and attitude, with motivational intensity prior to departure being a significant predictor of TOEIC gains. The findings underscore the idiosyncratic nature of studying abroad, and will be of use in designing and implementing post-overseas study programs.