The Rudjer Boskovic Institute in Zagreb is the largest multidisciplinary public research institute in Croatia, boasting half a century of tradition and excellence. Through the EU-funded project ‘Upgrade of the Rudjer Boskovic Tandem Accelerator Facility’ (RBI-AF) scientists aimed to stabilise and reinforce the existing research potentials of the RBI Tandem Accelerator Facility. The facility is used for research and applications in a range of fields, including nuclear and atomic physics, materials science and archaeology. The aim was to strengthen the Institute’s presence in the European Research Area (ERA) by increasing EU funding through collaborations across Europe and to meet increasing technological demands of various scientific fields. This effort involved upgrading the six MV tandem Van de Graaff accelerator to provide ion beams in a more efficient way. In-air end station (external beam) was improved to enable analytical measurements of samples that could not be exposed to vacuum. These included large objects which could not fit in the vacuum chamber as well as fragile and precious objects of cultural heritage. The ion microprobe was upgraded to allow better focusing of heavy ions. The new dual-beam end-station was constructed and installed to initiate materials modificiation studies with simultaneous irradiation of materials by multiple ions from two accelerators and using real-time analysis. The upgrading of the facility was disseminated to stakeholders through promotion brochures, a facility website and a workshop. The RBI-AF project upgraded the equipment of the RBI Tandem Accelerator Facility opening up possibilities for the facility to offer new subjects and activities, and to increase collaborations at the national and regional levels. Furthermore, it is expected to maintain and increase the lab’s involvement in cooperative research projects across Europe.