 This study investigated the acoustic properties of Poseidonia oceanica fibers, which are abundant in the Mediterranean Sea. The fibers were tested for sound absorption at various densities, and an analytical model was developed to predict the acoustic behavior of the fibers based on their density. The model was used to optimize sound absorbing panels made from the fibers. Additionally, the fibers were found to be naturally cleaned by waves and saltwater, making them ready for acoustic applications. This article was authored by Francesco Pompoli.