Increasing numbers of Chinese students are pursuing graduate degrees in Catalonia. Although highly proficient in both Castilian and English when they arrive, they find themselves in a bilingual society where Catalan, not Castilian, predominates both at universities and in the broader social context. Acquiring Catalan is hence important for both academic and social purposes. Using a longitudinal ethnographic study, this paper explores the factors motivating 25 Chinese students pursuing MA or Ph.D. programmes at Catalan universities to learn Catalan. Their motivation is examined over time using the L2 Motivational Self System, categorising it in "ought-to L2 self," "ideal L2 self," and "learning experience." The results reveal that Chinese graduate students in Catalonia are initially motivated to learn Catalan mainly by the ideal L2 self. The desire to integrate themselves into the Catalonia society is the most reported factor, followed by ought-to L2 self, such as academic needs and future career considerations. Once the learning process begins, learning experience becomes another important (de)motivation for the learners. Even when the initial future image has faded over time, personal satisfaction obtained from learning can still motivate learners to continue the investment.