A subsea antifouling sign and a method for mounting such a sign on a structure to be located subsea. The sign comprises a body of an antifouling material, and a first surface of the body has indicia or markings thereon. An adhesive layer or coating is provided on a second opposing surface, and a protective lining is located on the adhesive layer or coating. The method comprises removing the protective lining from the adhesive layer or coating; and attaching the subsea antifouling sign to the structure by adhering the adhesive layer or coating to a surface of the structure.