Flag of convenience fishing seriously undermines efforts to protect the marine environment. To counter this threat, Market Denial and International Fisheries Regulation rests on the logic of the most basic tenet of economics: if no market exists for a product then producers will cease to produce. Denying market access to the flag of convenience fishing fleet should significantly reduce instances of illegal, unreported and unregulated (IUU) fishing. In areas beyond national jurisdiction not only is market denial the most effective means of undermining the IUU fleet, it is, for most practical purposes, the only way to do so. To what extent, however, do the laws of the sea and international trade allow groups of States to close their markets to non-compliant fishing vessels?