Most of SIS's vessels operate in the waters around the Gulf and a large portion of the fleet is on long term contracts with leading oil companies including:

 

• Aban Offshore
• Aden Refinery
• Al Mubarak Overseas LLC
• Crescent Petroleum Co. (CPC).
• Dulam International Ltd.
• ENI
• Petrobras
• Global Marine Services
• Fugro Geoteam
• Lamnalco (Sharjah) Ltd.
• Fem Maritime
• Svitzer Wijsmuller
• NICO World.
• Qatar Navigation.

  

• Qatar Petroleum
• Repsol
• Saipem
• Schlumberger
• Stanford Marine Services
• Statoil
• Total Fina Elf
• VM Marine International Ltd.
• Cairn Energy - India
• AMASCO
• Britoil Offshore
• Caleb Brett M.E
• Zamil Marine Hercules Marketing International Ltd.