The practicum as a learning opportunity for prospective teachers of ESL or EFL remains underexplored. Most of the studies that have been documented in the TESOL practicum literature were conducted in either North America or a few Asian contexts with novice teachers. In this study the author used diaries by five Vietnamese EFL student teachers as sources of information to investigate their experiences during a 6-week practicum period. Findings show that these student teachers were strongly inclined toward the cooperating teachers' models of teaching rather than attempting to adapt the theories they had been taught in their practices and reflect critically on the process. The study has implications for the conduct of the practicum in Vietnam and possibly other similar contexts.