The proper conservation of underwater heritage is essential to honouring our past and understanding our history and culture. However, the underwater environment poses certain challenges, such as limited visibility, the absence of GPS signals, and the complexity of ocean currents, which complicate precise submerged localisation. Acoustic communication emerges as the predominant solution due to the effectiveness with which sound travels underwater. Nevertheless, developing accurate and reliable acoustic technologies has been significantly challenging due to cost constraints and technical complexity. This article presents the development of a low-cost buoy system prototype for underwater location. It aims to overcome the economic and technical limitations that have restricted the use of advanced technologies in preserving underwater heritage. By integrating cost-effective acoustic communication, this system seeks to provide an effective and accessible solution for the precise signalling of points of interest and the localisation of divers and remotely operated vehicles, boosting conservation and underwater exploration efforts. This work details the proposed architecture and the results obtained, discussing future improvements and research directions.