To keep up with the pace of technology, and for effective utilization of specific know-hows in implementation of projects, Sternax has associated itself with a number of reputable international companies. This has been either through joint venture agreements or on subcontracting basis.
Some of the international companies Sternax has cooperated with are:
| Chiyoda Corporation | Japan |
| Balfours | UK |
| Daelim | South Korea |
| EY | India |
| Fluor SA | South Africa |
| Falcon EPC Pte Ltd | Singapore |
| Prosernat, IFP Group Technologies | France |
| Rollechim Impianti | Italy |
| Snamprogetti, S.p.A. | Italy |
| Stamicarbon | Netherlands |
| Technip | France, Benelux, Germany and Italy |
| Tecnimont | Italy |
| Kinetics Technology (formerly Technip KTI) | Italy |
| The Shawinigan Engineering | Canada |
| ThyssenKrupp Industrial Solution (formerly Uhde) | Germany |
| Versalis ENI (formerly Polimeri Europa) | Italy |