A mooring system (10) is described for mooring a vessel to a floor portion of a body of water. The system (10) comprises a substantially rigid, elongate support member (12) having a connecting point (14) adjacent an upper end to which a vessel can be connected and being coupled adjacent a lower end (16) to an anchor on the floor portion, and a displacement buoy (20) slidably received on the support member (12) such that the displacement buoy (20) is capable of moving up and down the support member (12) with wave movement. The mooring system (10) also includes an elongate resilient member (26) operatively associated with the buoy such that upwards movement of the displacement buoy causes the resilient member to stretch. During use, the support member (12) extends in a substantially vertical orientation in a body of water and, when the support member (12) is urged to move off vertical, the buoy (20) is urged by the surrounding water to slide up the support member (12) and cause the resilient member (26) to stretch, the resilient member (26) thereby producing a self-centering force which acts to bias the support member (12) to return to the substantially vertical orientation in the body of water.