<p>The sound speed is a crucial parameter in various environmental processes occurring in shallow waters. Therefore, this study aimed to investigate how water parameters influence sound speed by collecting data from four shallow water sites namely Cilacap Fishing Port, Brebes Waters, Pangandaran Waters, and the Experimental Pond of the Faculty of Fisheries and Marine Sciences. Salinity, density, conductivity, and temperature were measured at four shallow water sites using a CTD, complemented with TDS (total dissolved solid), pH, and dissolved oxygen (DO) data from a water quality checker, while tidal information was obtained from the Indonesian Meteorology, Climatology, and Geophysical Agency (BMKG). Sound speed data from all observation stations were compared with established equations using simple linear regression, while variations in water parameters that directly or indirectly affect sound speed were analyzed through interpolation model, and further examined with regression linier model to determine their linear relationships with sound speed. Results showed that the accuracy of sound speed predictions across different equations varied among water types, with higher temperature and salinity variability leading to closer agreement with measurements, while narrower variability conditions resulted in greater deviations. The salinity had a stronger linear influence on sound speed compared to temperature, with TDS serving as a salinity indicator. Tidal dynamics and freshwater inflows also contributed to variations in salinity, impacting sound speed. Although the prediction model was generally reliable, the accuracy varied based on the specific conditions of each water location. This study underscores the necessity of understanding the interactions among different water parameters to enhance predictions of sound speed and the implications for managing aquatic resources and conserving ecosystems.</p>