Identifying integrated urban areas is an important issue for urban analysis and policy evaluation. In this paper, we extend the OECD’s methodology to identify Functional Urban Areas to countries where there is not commuting data. We do so substituting such socioeconomic flows by available information on road structure, which allow us to work with accessibility based on travel time. The main advantage of our procedure is its applicability to most countries in the world, as it only uses GIS data. In this paper we apply the procedure two border countries: Colombia, which has a recent census with commuting data, to calibrate our approach, and Ecuador, where there is not commuting census. We perform several sensitivity analysis and robustness checks to Ecuador with alternative sources of socioeconomic flows.