Spatial governance and planning systems empower the public authority to steer and control spatial development. Whereas most comparative studies on how this occurs focus on the European continent, less knowledge is available on the global South incre-mental urbanisation. The cases of three Latin American countries-Bolivia, Ecuador, Peru-are here discussed, highlighting the role played by the logic of necessity (and the resulting necessity-market) as the main driver of plot-by-plot urbanisation. The analysis shows that, in the three countries, spatial governance and planning systems are scarcely capable to address societal needs ex-ante and limit their activity to ex-post regularisation actions.