- Occidental
- Petroleum Development Oman(PDO)
- Oman Oil Refineries and Petroleum Industries Company (ORPIC)
- Daleel Petroleum
- Oman Oil Refineries and Petroleum Industries Company
- Oman Oil Company Exploration & Production LLC (OOCEP) and group of companies
- Petrofac
- Cadagua(spain)
- Hyundai Rotem
- Larsen & Toubro
- DNO
- Towell Engineeing
- Stomo
- Wadi Jizzi power plant
- Al Ghubra P&D plant
- Oman India Fertiliser Company(OMIFCO)
- Oman LNG(Liquefied natural gas)
- Amal Petroleum
- Medco Energy Company
- MB petroleum oil service company
- Public Authority of Electricity and water (PAEW)
- Haya Water
- Muscat Muncipality
- Sohar Muncipality
- Oman Electricity Transmission Company
- Majan Electricity Transmission Company
- Mazoon Electricity Transmission Company
- Muscat Electricity Transmission Company
- Ministry of regional muncipalities and Environment
- Ministry of health
- Ministry of defence Engg. Services
- Ministry of Agriculture and Fisheries
- STS-Tebodin
- STS
- Galfar
- Al Ansari contracting
- Wood Group CCC
- Al Turki
- Hitech Services
- Vale Oman