In this article, an alternative median filtering approach for acoustic side-scan sonar signals is presented. These acoustic signals are often degraded by a speckle noise which is inherent to the sonar, and the median filter is an effective tool to reduce it. However, its use has been resisted because it is time-consuming. Since the number of available large images is growing, more efficient smoothing algorithms are needed. This article describes a method for acoustic images median filtering which is simple to implement and uses fewer computational resources; a brief comparison with several existing algorithms is shown.