The increase in the number of mobile subscribers, coupled with the increase in mobile services is enough reason to monitor the QoS of mobile network operators frequently. This work looks into the QoS of network operators in Calabar, Nigeria, taking into consideration some KPIs ((CSSR, DCR, CST, HOSR, and network quality and network coverage). Analysis of data obtained after a benchmarking drive test shows that Globacom network was within NCC performance threshold for all network KPIs monitored. Also, MTN network performed poorly in HOSR but met the minimum benchmark in other network KPIs. Airtel network failed in the required DCR benchmark but was within the minimum benchmark for other KPIs while 9mobile failed in CSSR and DCR performance threshold but met the performance threshold for other KPIs. This result will be useful to the regulatory body, NCC, those in academic, RF engineers, network subscribers and especially, the network operators which we expect, will optimize their networks immediately.