Abstract: The present invention provides a hydrant locking device to be used in conjunction with a fire hydrant having locking nuts which includes, a base arm having a first base arm portion and a second base arm portion. A top arm extends upwardly from the base arm and includes a top arm cap for covering at least one of the locking nuts. The first base arm portion is detachably secured to the second base arm portion, wherein the base arm and the top arm are secured to the fire hydrant when the first base arm portion is secured to the second base arm portion.