An inflatable barrier system halts an approaching boat. A barrier support platform houses a pressurized gas source and a power supply and has a winch connected to a pair of cables. An inflatable barrier body member having a bow and stern is coupled to the pressurized gas source for inflation of the body member and the cables are connected to the bow and stern to deploy the inflated body member at the surface of the water and to maintain the bow above the surface and the stern below the surface of the water. A barrier controller provides signals indicative of the approaching boat to initiate the inflation of the inflatable barrier body member and the deployment of the inflated barrier body member at the surface with the bow above the surface and the stern below the surface without inflicting excessive damage to the boat or injury to its occupants.