This report presents the results of the study on “Lessons learned, best practices and epidemiological impact of the common European approach on digital contact tracing to combat and exit the COVID-19 pandemic”. The study was commissioned by the European Commission (EC), DG CONNECT, and carried out by empirica Communication and Technology Research from January to September 2022. The study provides a comprehensive overview of the approach and lessons learned from EU-level actions on cross-border interoperability and the epidemiological impact of digital contact tracing by Member States, EEA countries, Switzerland, and the United Kingdom. Contact tracing is an important public health intervention in the context of the COVID-19 pandemic that has seen high infectiousness and rapid spread of the virus throughout the world. Conventional contact tracing is used to detect and isolate possible infected individuals by tracing previous contacts as fast as possible. Digital contact tracing was explored early in the pandemic as a promising complementary solution to conventional contact tracing methods. Digital tools can capture anonymised interactions between individuals, identify contacts at risk of getting infected and subsequently issue alerts, all through a mobile interface. The technology is based on measuring signal strength between devices to trace proximity between users. There are several advantages of using digital contact tracing: it can capture interactions between individuals that otherwise cannot be identified via conventional contact tracing, including asymptomatic cases; it is a promising scalable approach when conventional contact tracing staff is overburdened by a high number of cases; it can support public health processes. The study examined 27 national digital contact tracing apps developed by European countries and deployed within a narrow timeline following the official declaration of the pandemic on 13 March 2020.