Positioning service is one of Wireless Sensor Networks’ (WSNs) fundamental services. The accurate position of the sensor nodes plays a vital role in many applications of WSNs. In this paper, a 3D positioning algorithm is being proposed, using mobile anchor node to assist sensor nodes in order to estimate their positions in a 3D geospatial environment. However, mobile anchor node’s 3D path optimization is off the subject. Accordingly, 3D path planning is slightly involved as precision schemes to minimize error boundaries and fault probabilities on mobile wireless anchor’s dynamics of precision positioning. In order to analyze proposed 3D path planning scheme’s performance, extensive WSNs simulations have been conducted using the NS-2 network simulator. Authors had to extend NS-2’s functionality to support 3D geospatial systems, features and calculations. Results indicate that path planning algorithm in discussion, achieves landmark performance and accuracy in average positioning error and percentage of positioned sensor nodes.