Over the years the need for mobile broadband had seen a great increment due to the demand of internet mobile users. In this research work, data size for Internet operation on UMTS mobile network operators on the University of Ilorin Campus was assessed. The study assessed three UMTS network operators using an Infinix T627 android smart phone and RantCell App. to measure the download and upload at the selected points on the University of Ilorin Campus. It was observed that the number of active subscribers with their relative position in a cell have a great effect on the performance of the networks and therefore, the authors recommend the need for the operators to improve their data sizes so as to enhance users’ satisfaction. Keywords: GSM, CDMA, ISP, PS, UMTS.