The aim of this study is to evaluate the effects of mobile technology on an outdoor experiential learning. We developed a mobile learning system with a learning flow to support an outdoor activity and then analyzed how PDA devices were incorporated and implemented in two classes of primary school students. The results indicate that knowledge creation was more effective in the class with PDAs than in the one without them. However, using activity theory as an analytical framework, we further discovered that underlying tensions provided rich insights into system dynamics and that technological affordances could be limited by a mismatch between the tools as such, and the way in which they were used by learners or were arranged by the instructor. The subtle human factors present in the use of technologies should be carefully considered. The influence of mobile devices on learner experiences in experiential learning is also thoroughly discussed.