Participations
| Country | Date joining the Action |
| Bosnia and Herzegovina | 19/09/2016 |
| Bulgaria | 08/09/2016 |
| Cyprus | 16/03/2016 |
| Czech Republic | 20/01/2017 |
| Denmark | 17/05/2016 |
| Estonia | 18/11/2016 |
| Finland | 21/03/2016 |
| France | 06/06/2017 |
| fYR Macedonia | 08/11/2016 |
| Germany | 15/05/2017 |
| Greece | 09/03/2016 |
| Hungary | 16/03/2016 |
| Israel | 10/03/2016 |
| Italy | 19/11/2016 |
| Netherlands | 30/03/2016 |
| Norway | 14/06/2018 |
| Poland | 13/06/2016 |
| Portugal | 02/05/2016 |
| Romania | 29/03/2016 |
| Serbia | 08/07/2016 |
| Slovenia | 29/09/2017 |
| Spain | 03/05/2016 |
| Switzerland | 30/06/2016 |
| United Kingdom | 08/04/2016 |
Total: 24
COST Near Neighbour Countries
| Institution Name | Country |
| ST. Petersburg State University | Russian Federation |
| Institute of Applied Physics, Rus. Acad. Sci. | Russian Federation |
| Yerevan Physics Institute | Armenia |
| Institute of Geophysics and Engineering Seismology | Armenia |