The extraction of the archaeological pieces from the marine environment can mean an increase in its deterioration, being, one of the current trends, the in situ conservation of them. Once the object is submerged in water, traditionally three types of deterioration are defined: chemical (precipitation of salts); physical (erosion); biological (colonization of microorganisms). To these three processes of deterioration we should add the presence of micro-plastics. The main problem caused by the toxicity of plastics is due to the toxicity of the additives added to them, so that if the plastic is not degradable, its toxicity remains in seawater for hundreds of years. It is therefore of great interest to determine the presence of plastics, micro-plastics and their additives, in seawater. Raman spectroscopy is a technique that allows the identification and characterization of mineralogical compounds in aqueous media. The aim of this work is to study the identification of plastics, micro-plastics and their additives in seawater by means of spectroscopic techniques.