This paper maps the evolving data localisation landscape. It shows that the number of data localisation measures is on the rise and that the measures themselves are becoming more restrictive. The paper highlights the need to better understand and monitor the evolving regulatory environment with a view to enabling empirical analysis of the economic and societal implications of data localisation. This is an issue which is particularly important in the context of ongoing discussions on data localisation, be they in preferential trade agreements (PTAs) or in the context of the WTO Joint Statement Initiative on e-commerce.