The evolution of regulations concerning biocidal products aims to increase protection of the environment (e.g., EU Regulation No 528/2012) and requires the development of new non-toxic anti-fouling (AF) systems. The development of these formulations implies the use of ingredients (polymers, active substances, additives) that are devoid of toxicity towards marine environments. In this context, the use of erodable antifouling paints based on biodegradable polymer and authorized biocides responds to this problem. However, the efficiency of paints could be improved by the use of specific additives. For this purpose, three additives acting as surface modifiers were studied (Tween 80, Span 85 and PEG-silane). Their effects on parameters involved in antifouling efficiency as hydrophobicity, hydration and copper release were studied. Results showed that the addition of 3% of additives modulated hydrophobicity and hydration without an increase of copper release and significantly reduced microfouling development. Efficient paints based on biodegradable polymer and with no organic biocide could be obtained by mixing copper thiocyanate and additives.