| Participant No* | Participant organisation name | Contact | Country |
| 1 (Coordinator) | Istituto Nazionale di Astrofisica (INAF) | Luigi Piro | Italy |
| 2 | Space Research Organization
Netherlands (NWO-I/SRON) |
Jan-Willem den Herder | The Netherlands |
| 3 | Max-Planck-Gesellschaft (MPG) | Vadim Burwitz | Germany |
| 4 | National Observatory of Athens (NOA) | Ioannis Georgantopoulos | Greece |
| 5 | University of Leicester (ULEIC) | O’Brien, Paul T. | United Kingdom |
| 6 | Universidad de Alicante (UA) | Jose Miguel Torrejon | Spain |
| 7 | European Gravitational Observatory (EGO) | Stavros Katsanevas | Italy |
| 8 | Istituto Nazionale di Fisica Nucleare (INFN) | Michele Punturo | Italy |
| 9 | Centre National de la Recherche Scientifique (CNRS) | Vincent Tatischeff | France |
| 10 | Gran Sasso Science Institute (GSSI) | Marica Branchesi | Italy |
| 11 | Universitè de Genève (UNIGENEVE) | Marc Audard | Switzerland |
| 12 | Agencia Estatal Consejo Superior de
Investigaciones Cientificas (CSIC) |
Maite Ceballos | Spain |
| 13 | Commissariat à l’énergie atomique et
aux énergies alternatives (CEA) |
Philippe Laurent | France |
| 14 | Consiglio Nazionale delle Ricerche (CNR) | Marcello Coreno | Italy |
| 15 | Thales Alenia Space Italia SPA (TAS) | Paolo Bastia | Italy |
| 16 | University College Dublin (NUID UCD) | Lorraine Hanlon | Ireland |
| 17 | Université de Liège (ULIEGE) | Karl Fleury-Frenette | Belgium |
| 18 | Università degli Studi di Ferrara (UNIFE) | Piero Rosati | Italy |
| 19 | Università degli Studi di Palermo (UNIPA) | Marco Barbera | Italy |
| 20 | Ceske Vysoke Uceni Technicke V Praze (CVUT) | Rene Hudec | Czech Republic |
| 21 | Centrum Astronomiczne Im. Mikolaja
Kopernika Polskiej Akademii Nauk (NCAC) |
Agata Rozanska | Poland |
| 22 | Leiden University (ULEIDEN) | Joop Schaye | The Netherlands |
| 23 | Physikalisch-Technische Bundesanstalt (PTB) | Joern Beyer | Germany |
| 24 | Università degli Studi di Genova (UNIGE) | Gatti Flavio | Italy |
| 25 | Eberhard Karls Universität Tübingen (EKUT) | Andrea Santangelo | Germany |
| 26 | Ludwig-Maximilians-Universität München (LMU MÜNCHEN) | Klaus Dolag | Germany |
| 27 | Associação do Instituto Superior Técnico para a Investigação e Desenvolvimento (IST-ID) | Miguel A. Reis | Portugal |
| 28 | Universiteit van Amsterdam (UvA) | Phil Uttley | The Netherlands |
| 29 | Swhard srl (SWHARD) | Paolo Dondero | Italy |
| 30 | Johannes Gutenberg-Universität Mainz (UMAINZ) | Uwe Oberlack | Germany |
| 31 | Tartu Ülikool (UTARTU) | Jukka Nevalainen | Estonia |
| 32 | Laboratório de Instrumentação e Física Experimental de Partículas (LIP) | Rui Curado Silva | Portugal |
| 33 | Danmarks Tekniske Universitet (DTU) | Irfan Kuvvetli | Denmark |
| 34 | Eötvös Loránd Tudományegyetem (ELTE) | N.A. Exit Project on 30/06/2020 | Hungary |
| 35 | University of Bath (UBATH) | H.J.Van.Eerten | United Kingdom |
| 36 | Stiftung Deutsches Elektronen-Synchrotron (DESY) | David Berge | Germany |
| 37 | Kaon GmbH (KAON) | Kevin Phelan | Germany |
| 38 | COSINE Research BV (CR) | Max Collon | The Netherlands |
| 39 | Masarykovy Univerzity | Norbert Werner | Czech Republic |
