Belgium’s sub-state entities play an important role in the external representation of the Belgian Kingdom. This includes the proviso that the sub-state entities can represent Belgium in the meetings of the EU’s Council of Ministers. The article examines to what extent the Belgian model can be used as a model for exportation to other federal, regional and decentralised states. It mainly focuses on a comparison with Spain. The article starts with an overview of the complex Belgian institutional framework, as this must be understood in order to judge any potential exportation of the Belgian model. This framework is based upon the principle “in foro interno, in foro externo”, which means that each power that belongs at an internal level to a region or a community should be exercised by them at an external level. No other Member State possesses a similar constitutional principle. This complicates its potential for exportation at a fundamental level, though it might bring new ideas for the further development of the regional Spanish state.