Reverse osmosis (RO) has been established as a reliable process for seawater desalination. The reliability of RO technique depends upon the extent of the pretreatment that must be designed to reduce the suspended and colloidal materials in the feed water. Three pretreatment systems were tested and evaluated at Doha Research Plant (DRP) in Kuwait. The beachwell seawater intake and microfiltration systems have been identified as promising techniques to replace the conventional pretreatment. This paper discusses the performance evaluation of the three tested seawater pretreatment systems. Based on one year of actual operational data, it was concluded that beachwell seawater intake, where it is possible to construct, is the most reliable source of feed water for (RO) plant, followed by microfiltration system.