Abstract: Transducers or hydrophones have great influence on sonar performances. As techniques progress rapidly, sonar transducers have been improved significantly in terms of analyzing methods, design theories, and materials used, leading to substantial improvements in the transducer performance. Terfenol-D transducers, PMN-X transducers, piezo-composite transducers, vector hydrophones, low-frequency and wide-area PVDF hydrophones, and fiber-optic hydrophones are some of the current research focuses. This paper reviews the recent advances in sonar transducers, specifically the above-mentioned types developed since 1980s.