Guided by design-based research and the notion of seamless learning, we have designed a learning activity in mathematics where mobile and web technologies support transitions between outdoor and indoor learning contexts. The students' initiatives during the self-regulated outdoor part of the activity are scaffolded by the use of mobile technologies and activity prompts which provide means and demands for on-the-spot oral and visual recordings of the groups' experiences and strategies. We argue that the high quality of mathematical content in the recordings is due to several contributing factors: the choice of appropriate technological support, the informal settings, the availability of relevant physical references, and the immediate recording based on fresh experiences. Our data suggests that the rich nature of the recordings contributes to the effective transition and communication of the outdoor experiences to the classroom's learning context where these experiences are shared and discussed with peers. Finally, we discuss design issues related to the role of the teacher, as well as the structure of the entire activity and the implications for future design iterations.