The Overtopping BReakwater for Energy Conversion (OBREC) is a new typology of overtopping wave energy converter (OTD) integrated into a traditional rubble mound breakwater. The device can be considered as an innovative non-conventional breakwater that has the same functions as the traditional structures with the added-valued of the energy production. The paper presents a comprehensive overview of the OBREC, offering a synthesis of the complete design process, from the results of the two complementary test campaigns in small scale carried out in 2012 and 2014 at Aalborg University, to the description of the full-scale device installed in Naples in 2016. The device represents the first OTD device in full-scale integrated into an existing rubble mound breakwater and it has been equipped by an instrumental apparatus to measure its response to the wave interaction. The monitoring of the full-scale device in the port of Naples, particularly during storm conditions, is aimed to study the scaling effects in wave loading and the overall performance of this breakwater-integrated OTD, included performance in terms of the energy production.