The EU counts approximately 2400 islands, totalling a population of nearly 15 million. Islands are particularly vulnerable to climate change but enjoy a naturally high potential of renewable energy sources to harness. As a consequence, the EU considers them as energy transition laboratories and wishes to decarbonise 1000 of them by 2030. If this outcome might be technically possible, it requires fit-for-purpose EU and national legal frameworks as well as a strong emphasis on the fairness aspect of this transition. This article firstly analyses the concept of Just Transition and its use in international law and EU policy and law. It proposes the notion of ‘concentric Just Transition’ to qualify the current use of this concept in EU initiativ...