Proposed herein are antifouling coating compositions containing bis-trialkylstannyl derivatives of chlorinated polycyclic dicarboxylic acids, of the general formula ##STR1## wherein R is a lower alkyl, R'=H,CH.sub.3, n=0,1, which are obtained by a condensation reaction of anhydrides of the respective dicarboxylic acids with hexaalkyldistannoxanes R.sub.3 SnOSnR.sub.3, wherein R is a lower alkyl, in the medium of an organic solvent.