The physiographical features of the Galician sea, in particular its temperature, marine currents and plankton richness, have turned its waters into one of the most biologically diversified marine regions of the planet. The 1500 km of shorelines from this Northwest Iberian region are dotted with rías (Galician fjords) where settlements devoted to fishing and trade have existed since prehistoric times. These activities left abundant testimonies in terms of archaeological deposits. In recent decades, urban/industrial development, as well as a number of natural agents (e.g., storms, sea level rise, climate change), is rapidly erasing the evidences of this rich cultural heritage. Loss of fish and shellmiddens in particular will hamper our ability to infer traditional lifeways, doing away with evidence that is crucial to monitoring past climatic changes and to inferring those biological conditions under which marine species and coastal populations thrived in the past. This paper surveys some issues dealing with the coastal bio-archaeological heritage of Galicia, and the risks these deposits face. It concludes with a proposal to save this increasingly threatened marine heritage.