Abstract: The system and method for pretreating turbid seawater utilizes polyelectrolyte dosing, clarification through a clarifier system and centrifugation in a decanter centrifuge followed by microfiltration to treat seawater prior to its injection through a desalination plant. The system for pretreating turbid seawater includes a static mixer for mixing a polyelectrolyte with a stream of turbid seawater to produce a polyelectrolyte-treated seawater mixture. At least one clarifier tank is in fluid communication with the static mixer for receiving the polyelectrolyte-treated seawater mixture and removing a first portion of solids therefrom to produce a clarified seawater mixture. A decanter centrifuge is in fluid communication with the at least one clarifier tank for receiving the clarified seawater mixture and removing a second portion of solids therefrom to produce centrifuged seawater.