Despite the increasing popularity of mobile information systems, the actual processes leading to the innovation of mobile technologies remain largely unexplored. This study uses Action Research to examine the innovation of a mobile RFID technology. Working from Activity Theory, it departs from the prevalent product-oriented view of innovation and treats technology-in-the-making as a complex activity, made possible through the interaction of manufacturers, their organisational clients and their respective mobile workers. The lens of a normative Interactive Innovation Framework reveals distinctive interaction problems that bear on the innovation activity. In addition to difficulties emerging from dissimilar motivations for the innovation project, the mobile setting presents unique contradictions based on the geographical distribution of its participants, the diverse role of mobile technology, the complexity of interacting through representations and the importance of the discretion with which mobile work activities are carried out today.