Abstract: Aiming at the requirements of underwater long-endurance, long-distance, and high-precision positioning, the traditional multi-beacon acoustic positioning system struggles to meet the needs of underwater navigation applications due to the limitations of complex layout and high cost associated with beacon deployment. Single-beacon underwater acoustic positioning technology has become a research hotspot owing to its advantages of simple structure, flexible deployment, and strong concealment. This paper systematically reviews the principles, methods, and research progress of single-beacon underwater acoustic positioning technology. The two major technical systems—based on geometric positioning and state estimation—are compared and analyzed. The main error sources in underwater acoustic ranging and corresponding compensation strategies are discussed. In combination with actual application requirements, future research directions are prospected. By summarizing domestic and international research achievements, this paper aims to provide a systematic reference for further research and engineering applications of single-beacon technology.