Underwater localization using acoustic signals is one of the main components in a navigation system for an AUV as a more accurate alternative to dead-reckoning techniques. While different methods based on the idea of multiple beacons have been studied, other approaches use only one beacon, which reduces the system costs and deployment complexity. The inverse approach for single-beacon navigation is to use this method for target localization by an underwater or surface vehicle. In this paper we present a method of range-only target localization using a Wave Glider ™, for which simulations and sea tests have been conducted to determine optimal parameters to minimize acoustic energy use and search time and to maximize location accuracy and precision.