Location updating is provided in a mobile communication system which visitor location registers, each of which maintains the subscriber and location data of mobile subscribers visiting its service. In addition, there are sub-location registers for a particular sub-area of the service area of a visitor location register. A sub-location register is arranged to forward the first location updating of a mobile station arriving into the sub-area to the visitor location register to the service area of which the sub-area belongs, in order to update the location data of the visitor location register and to copy the necessary subscriber data from the visitor location register to the sub-location register. The sub-location register is also arranged to independently handle the subsequent location updatings of the mobile station in the sub-area in such a manner that the location of the mobile station is updated only in the sub-location register.