Outdoor play is an important activity in young children's lives which should be encouraged. Cultural and social demographic data inform of decreasing numbers of children and shortage of playgrounds around urban areas. Technological advancements such as television and computer games have influenced children's recreational activities so that they prefer to play indoors rather than outdoors. In order to motivate children to play outside we propose technologically supported play tool titled 'SoundTag'. This is a Radio Frequency Identification (RFID) based wearable system that uses sound interaction. We deployed two types of SoundTag system. The first one is the interactive wearable system with sound feedback. And the second one is interactive sound feedback with sound recording system. In this paper, we detail the concept of the system and related design theory. A pilot experiment with the first SoundTag system is reported where we observed the system in use. And followed by the observation of the experiment, the second SoundTag system is deployed and the preliminary experiment is reported.