An improved boat docking stabilizer device to an economic, compact and reliable boat mooring apparatus that stabilizes a moored boat for safe boarding and de-boarding of passengers while permitting the boat to roll free with the waves thus preventing damage to either the dock or the moored boat. An improved boat docking stabilizer device which may be used in pairs for mooring a boat to a dock structure or the like. This boat docking stabilizer device includes an adjustable backboard mounted perpendicularly to a dock structure by fastening means, an adjustable vertical support bracket mounted to the backboard, a hitch ball coupler pivotably mounted to the vertical support bracket for receiving a ball hitch mounted on a boat, and means for locking the hitch ball coupler in a ready position and in a locked position.