This paper reports an intervention study on Singapore primary five (fifth Grade) students' ICT (information and communication technology)-mediated Chinese idiom learning. We introduced "seamless learning" to the learning design, that is, the bridging of formal and informal learning, and individual and social learning, conforming to the current trend of language learning which emphasizes more on communicative and authentic learning activities. Our study lasted for ten months. In the formal learning context, the teacher conducted in-class contextualized learning activities and group activities. In the informal learning context, students made sentences by using the idioms to describe their encounters in day-to-day life and post them onto a class wiki space for sharing peers' review. Meanwhile, students learned from and performed peers' views on the wiki by commenting on, correcting or improving their peers' sentences. Through our analysis on the empirical data, it was found that the new ICT-mediated learning could effectively help students synergize the formal and informal, as well as the individual and social language learning spaces. (Contains 8 figures and 1 table.)