Abstract: A marine antifouling material providing an antifouling surface for use in sea water comprises a layer of inert, water-insoluble, flexible and extensible elastomeric carrier material having embedded therein a single layer only of a plurality of copper or copper alloy particles of substantially uniform size and shape exposed at the outer surface of the material to provide a multiplicity of generally evenly sized discrete copper areas in the inert material continuum surface thereof. The particles are insulated from each other and from an opposed inner surface of the material.