Energy transition in islands constitutes a major challenge. Apart from a necessity, it can also be a great opportunity for sustainable social and economic development. Toward this direction, a new, promising movement has emerged recently in Greek islands. Straight from the roots of the insular population, development of energy communities comes as the result of increased awareness of local people, raised also by the legacy of lighthouse projects and initiatives. Kythnos, Ikaria, Sifnos, Tilos, Agios Efstratios, Crete, and Chalki, are all islands that have embraced the implementation of successful, local-scale innovation projects and/or initiatives, generating meaningful results across different energy aspects and contributing to positive social change. Our study provides an overview of the broader energy transition aspects in Greek islands, discusses the impact of the aforementioned exemplary cases, and further elaborates on the model of energy communities. According to our analysis, leveraging on the experience of lighthouse projects and initiatives, and on the dynamics of the emerging energy community movement, could lead to increased social and economic benefits for the insular populations, to broad public acceptance, and to minimum environmental impacts for the islands’ natural ecosystems.