Over the past decades, the EU has developed a patchwork of regional strategies and institutions stretching from the Mediterranean to the Arctic. The EU’s involvement often started without a formal legal basis. The use of soft law instruments frequently allowed to avoid questions of competence delimitation. At the same time, a gradual institutionalisation of some cooperation structures could be observed, most notably in the Southern neighbourhood. The ambition to upgrade the EU’s status in international organisations and fora in accordance with the objectives of the Lisbon Treaty faced significant difficulties. This is due to actions of the EU’s Member States, which want to pursue their national interests in a particular region, or because of the resistance of third states, which do not necessarily see the added value of a unified EU representation. The result is a significant diversity, and a lack of consistency, in the EU’s institutional relations with international and regional actors in its neighbourhood.