- EU member states’ governments – Austria, Bulgaria, Croatia, France, Germany, Greece, Italy, Slovenia, Poland as well as the United Kingdom (EU member until January 2020)
- Governments of the six Western Balkans:
- civil society
- businesses
- The EU institutions – The European Commission (EC), European External Action Service (EEAS), and the member state holding the Presidency of the Council.
- International financial institutions
- Regional initiatives – Regional Cooperation Council (RCC), South East European Transport Observatory (SEETO), Energy Community (EnC), Central European Free Trade Agreement (CEFTA), Regional Youth Cooperation Office (RYCO), Regional Anti- Corruption Initiative (RAI).
