The brown seaweed Sargassum poses an increasingly significant environmental challenge along the coasts bordering the Atlantic Ocean, particularly in the Caribbean and in the equatorial Africa. Vast floating expanses of this seaweed accumulate in the sea and along the coasts, posing obstacles to fishing and tourism activities. In recent years, efforts have been underway to develop various projects aimed at utilizing these algae as a resource for various industrial applications. In this context, the following article will propose a design approach for sound-absorbing panels made from sun-dried Sargassum. This approach includes an acoustic and physical characterization of the material as a function of its bulk density, an analytical modeling of the acoustic field within the material considered as an equivalent dissipative fluid, and a prototype proposal for modular sound-absorbing panels with a significant design content.