A new archaeological research project analyses the history of Isla del Fraile (Águilas, Spain), a small island off the coast occupied since at least Roman times. Its isolation means that the sea has always conditioned its connectivity and relationship with land. Despite some underwater studies carried out in previous decades, its underwater surroundings, El Hornillo Bay, continue to be relatively unexplored. In parallel to the excavation work on the island's surface, an underwater survey was carried out in the area, which is known for its archaeological wealth. The objectives of this paper are to study the underwater contexts associated with the archaeological site, to determine whether there were any ports or anchorages and to analyse the phases of greatest activity in the bay between Antiquity and the Modern Age. New data are provided, and earlier finds, either previously unpublished or from private donations, are also reviewed. The findings are discussed and related to their local and interregional contexts. The main purpose is to offer a new contribution to the study of the maritime cultural landscape of the Western Mediterranean through a region underrepresented by research.