The once-through multi-stage flash (MSF) desalination plant with feed cooler is a desalination system utilizing a feed water cooler. Particularly, the plant includes a conventional MSF system, with a separate water cooler for cooling the seawater or brine that is input into the system, prior to the passage of the brine into the condensation conduits and brine heater. In use, the cooled brine is pumped, under pressure, through at least one conduit that passes through a plurality of flash chambers. The brine is then heated and injected into the plurality of flash chambers, where it is flashed into steam. The steam condenses on an external surface of the at least one conduit, and the condensed water is then extracted from the plant.