The water is an imperfect acoustic medium, acoustic energy can lost due to absorption and scattering thus resulting in transmission loss. The value of transmission loss in water is an important thing to know, for example in the application of active acoustic. This study aim is to determine the value of transmission loss in Tanjung Intan's cruise line, Cilacap. The acquisition of vessel's sound data was obtained by hydrophone and vessel data (distance) by CCTV. Both sound data and vessel data were connected to personal computer to record the audio and visual signal synchronously for three consecutive days. Results showed that vessel characteristics such as intensity, frequency and interval duration have a value of 43.35 (dB), 6613.54 (Hz) and 216.15 (ms) respectively. While the value of water absorption coefficient has a range of 500-900 dB/km, the estimated transmission loss value was between 5-11 dB/km.