This article reviews developments in ‘mobile methodologies’, looking at the theory, technologies and practice of mobile methods. We focus specifically on methods where the research subject and researcher are in motion in the ‘field’, and seek to understand what difference mobile methods can make to research. Drawing on the broader mobilities paradigm, we identify the key tenets of mobile methodologies, and then discuss the role that technologies such as geographical information systems can play in opening up this new approach to research. The article reviews past and present work that has utilised mobile methods, highlighting key opportunities and challenges. We consider current attempts to use geographical information systems to rigorously investigate the effect that walking has on an interview process, and conclude by summarising the potential for mobile methods to inform social scientific research.