The corrosion characteristics of copper were investigated in the palk bay waters of the Mandapam coast, India over a period of a year. This work comprises both field exposure as well as laboratory studies. The experimental method included determination of corrosion rate by weight loss measurement and analysis of the corrosion products by x-ray diffraction. The XRD analysis of the products On copper threw more light on the nature of the oxide film formed and their impact on the overall corrosion rate/bio fouling of the material. The effect of biofilm on corrosion behaviour of copper was investigated by Tafel polarization and impedance techniques. The annual (oct'96-sep'97) corrosion rate of copper was 0.045 mmpy with no fouling.