This chapter reviews the practical applications and future development directions of sound-based positioning systems across diverse domains. It first examines current real-world deployments in indoor robotics, smart buildings, industrial automation, and underwater navigation, highlighting the environmental conditions and technical constraints that shape system design. Based on these applications, the chapter discusses the integration of acoustic positioning with emerging technologies such as computer vision, sensor fusion, and artificial intelligence. Finally, key challenges and open research questions are identified, and future perspectives are outlined, positioning acoustic localization as a critical enabling technology for robust, high-precision navigation in GPS-denied environments.