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.