This test method covers the laboratory determination of the rate at which copper is released from an antifouling (AF) coating in substitute ocean water. The practical limits for quantifying copper release rates by this method are from 1.8 to 500µg cm^-2d^-1. This range may be extended to 0.2 to 500µg cm^-2d^-1 if the analytical procedure described in Appendix X1 is followed.