The first goal of this work is to collect available physical geographic data on islands and to elaborate measures of insularity. We then evaluate whether and when insularity can become ‘bad’ geography in terms of poor economic performance. We find that two important dichotomies are present: states that are islands (full insularity) perform worse than countries that have islands (partial insularity). Within the group of island-states, isolation is the crucial dimension associated with low GDP, less the dispersion of the land. Instead, being coastal and having islands is associated with better results than only having direct access to the sea.