This chapter describes the latest developments which have expanded the European Union’s legal framework to the Energy Community Contracting Parties and enabled their integration into the internal market for electricity, in particular their adherence to the SDAC and the SIDC. This is not only crucial for the Energy Community but also for the European Union and its European Green Deal, the success of which is linked to its neighbours and partners. The envisaged extension is substantial in size and its implementation requires all involved parties to proceed fully committed and coordinated. Hence, this chapter introduces the Energy Community, its institutional set-up and legal framework, including the Electricity Integration Package. Besides getting to know the electricity markets of the Contracting Parties, the reader is familiarized with important implementation steps and preconditions to successfully enlarge the SDAC and the SIDC across Europe.