From the very beginning of liberalization of the electronic communications sector in the 1990’s, competition law has played a key role, in particular by adopting decisions and legislation based on Article 106 of the Treaty on the Functioning of the European Union (“TFEU”) combined with Articles 101 and 102 TFEU. Today, the sector specific rules that regulate the electronic communications sector are still largely built on competition law concepts such as market definition, significant market position, and remedies. The liberalization process originally led to an electronic communications sector that was largely characterized by a dichotomy between incumbent operators and new entrants. As a result, antitrust enforcement has largely focused on abuse of dominance cases. Still, the prohibition of restrictive concerted practices has also been visibly relevant. For instance, the 1991 Guidelines on the application to competition law to the telecom sector included an analysis of Article 101 TFEU, as did the 1998 Access Notice. Albeit less often than under Article 102 cases, the Commission has investigated certain cases under Article 101 TFEU, notably in relation to roaming and network sharing agreements. In more recent years, the Court of Justice (CJEU) has also widely applied Article 101 in the telecom sector, in view of capturing situations whereby parties exchanged information, irrespective of whether such exchange enabled the parties to coordinate. Beyond competition law, regulation has typically taken over the role of framing permissible agreements and concerted practices in the electronic communications sector. For example, the regulation of roaming agreements since 2007 has limited the contractual freedom to set prices at wholesale and retail level. Similarly, net neutrality provisions included in the Regulation on open Internet access limit the flexibility of mobile network operators (“MNOs”) to conclude agreements for prioritization of traffic. Today, with the advent of 5G, the deployment of fiber and the convergence of fixed/mobile networks and services, competition and regulatory authorities are faced with yet another leap in technological advancement impacting how to assess and safeguard fair competition. This article overview examines the period 2013-2019 and reviews precedents in the areas of horizontal and vertical agreements.