Mobile Wireless Sensor Networks (MWSNs) has significant applications that provide free moving for sensor nodes and flexible communication with each other. MWSNs perform many improvements in energy consumption, network lifetime, and channel capacity than static WSNs. The MWSNs need more sophisticated routing protocols than static WSNs due to the unfixed topology based on nodes mobility. This paper presents an Improved Mobility based Genetic Algorithm Hierarchical routing Protocol (IMGAHP) to handle the packet delivery ratio problem in MGAHP and maximize the network stability period. The proposed protocol is based on two main points. Firstly, utilizing the optimization process (Genetic Algorithm (GA)) to detect the optimum location of Cluster Heads (CHs) and their numbers. Secondly, reassigning timeslots allocated for sensor nodes which moved out of the cluster or didn’t have data to send, to nodes registered in secondary Time Division Multiple Access (TDMA) schedule or new joined mobile nodes. Several experiments are implemented on the proposed IMGAHP protocol using the Matlab simulation program to appraise and compare it with MGAHP and other previous protocols. It is shown from the results that the proposed IMGAHP gives preferable enhancement in packet delivery ratio, energy efficiency, and network lifetime than all previous protocols.