Propose the mobility of a sink in improved energy efficient PEGASIS-based protocol (IEEPB) to advance the network lifetime of Wireless Sensor Networks (WSNs). The multi-head chain, multi-chain concept and the sink mobility affects largely in enhancing the network lifetime of wireless sensors. Thus, we recommend Mobile sink improved energy-efficient PEGASIS-based routing protocol (MIEEPB); a multi-chain model having a sink mobility, to achieve proficient energy utilization of wireless sensors. As the motorized movement of mobile sink is steered by petrol or current, there is a need to confine this movement within boundaries and the trajectory of mobile sink should be fixed. In our technique, the mobile sink moves along its trajectory and stays for a sojourn time at sojourn location to guarantee complete data collection. We develop an algorithm for trajectory of mobile sink. We ultimately perform wide-ranging experiments to assess the performance of the proposed method. The results reveal that the proposed way out is nearly optimal and also better than IEEPB in terms of network lifetime.