The document describes a proposed sink mobility based energy efficient routing protocol for wireless sensor networks. The protocol uses both a static centralized sink and a mobile sink that follows a predetermined path with 4 sojourn locations. This is aimed to improve network lifetime by balancing energy load across nodes. Simulation results show that the proposed approach with a mobile sink performs better than the Threshold sensitive Energy Efficient sensor Network (TEEN) protocol alone in terms of number of alive nodes, number of cluster heads, and number of packets sent to the base station over multiple rounds. Using a mobile sink helps scatter the energy load in the network and extends lifetime compared to only using a static sink.