This paper reports on an inquiry that explored the role of metapragmatic awareness of L2 learners in Hong Kong, and the influence it has on language choices when addressing requests in English. Simulated open role-plays and retrospective interviews were employed to examine how mainland Chinese undergraduates assess, plan and produce their utterances. The results display that participants’ self-monitoring of pragmalinguistic and sociopragmatic knowledge may contribute to metapragmatic awareness; their oral performance in target language pragmatics depends on these two types of knowledge, as well as on self-evaluation of mediating factors like cognitive task demand and learner subjectivity. By bridging the gap between what learners say and why they say it, this paper shows how metapragmatic awareness mediates the process of real-time L2 pragmatic performance and how it appears from such a mediated process.