Abstract: The present invention related to self-polishing marine antifouling paint compositions comprising rosin or rosin equivalent(s), optionally fibres, and one or more polymeric flexibilizer component(s). The rosin part of the paint preferably comprises ammonium or metal salts of rosin and/or rosin qualities having a low content of conjugated double bonds, i.e. a low degree of unsaturation. The non-crystalline flexibilizer components have a glass transition temperature, Tg, in the range of −45 to 25° C. and are preferably selected from poly(meth)acrylates, polyacrylamides, copolymer and terpolymers thereof, acrylamide resins, acrylic acrylamide resins, polyvinyl ethers, polyvinyl esters, polyester, polyoxy-C1-5-alkylenes, polyurethanes, and epoxy esters. The fibres are preferably natural or synthetic inorganic or organic fibres or metal fibres. The paints have improved mechanical properties such as strength and resistance towards weathering.