This study aims to investigate and compare the relationship between immersion and motivation in two different groups of student teachers who enrolled in an immersion programme. With a group of student teachers whose social and cultural backgrounds are different – one group is from Mainland China and one is from Hong Kong – though they both are of Chinese ethnicity and speak the same Chinese variety, the reasons behind their studying a postgraduate programme and going on an immersion can be different. The method of data collection adopted for this study was a qualitative paradigm. In-depth interviews, both pre- and post-immersion, were conducted. Participants were also encouraged to send e-mails to the researcher during immersion that reflected on their experience. Results show that Mainland participants were motivated by desires to enhance their pedagogical knowledge in EFL teaching in order to satisfy implementation constraints in their homeland. In contrast, Hong Kong participants were primarily interested in improving their language proficiency in order to satisfy the mandatory language assessment required for graduation. Both groups, however, saw cultural enrichment as their secondary reason for undertaking immersion, in that it allowed them to better understand the culture behind the language and thus become better English teachers. Copyright © 2019 Academy Publication.