This chapter explores mobile phone operators, big data and urban analysis. The focus is on exploring methodological approaches based on the existing state-of-the-art of urban analysis and, in particular, on the analysis of big data obtained from mobile phone operators. Urban analysts have begun to explore the application of ‘new’ sources of big data to understanding cities. Perhaps these big data sources need to be relabelled as another form of microdata as they chart the everyday and often second-by-second interactions between people, place and space. The analysis of big data is beginning to reveal the dynamics of cities and diurnal patterns. Nevertheless, this understanding of people and place is yet to be incorporated in to mainstream urban analysis and in to models intended to predict the growth patterns of cities and regions. This chapter highlights the opportunities for developing a big data informed view of city-regions.