Quintessa actively seeks to work in partnership with a network of organisations and individuals around the world, including:
| UK | British Geological Survey | |
| DGP International | ||
| Enviros Consulting | ||
| Faulkland Associates | ||
| Greenstreet Berman | ||
| IC Consultants | ||
| In Situ Solutions | ||
| Safety Assessment Management | ||
| University of Bath | ||
| University of Bristol | ||
| University of Reading | ||
| URS Corporation | ||
| Japan | JGC Corporation | |
| Kajima Corporation | ||
| Mitsubishi Corporation | ||
| Mitsubishi Materials Corporation | ||
| France | OXAND | |
| USA | American Geological Services Inc. | |
| GoldSim Technology Group | ||
| Monitor Scientific LLC | ||
| Spain | Enviros Spain SL | |
| Iberinco | ||
| Sweden | JA Streamflow AB | |
| Kemakta Konsult | ||
| South Africa | Aquasim Consulting | |
| Romania | Centre of Technology and Engineering for Nuclear Projects | |
| Geo Prospect | ||
| MATE-FIN | ||
| Slovak Republic | Decom Slovakia | |
| WERT |