Resources of marine environment are suffering from over-exploitation by Flags of Convenience vessels; which refer to vessels registered in foreign countries known as Open Registry countries. These countries usually do not fulfill the obligations incumbent upon them as flag states towards the vessels flying their flags, in an attempt to attract more registries. They, inter alia, adopt loose enforcement measures against illegal activities by their vessels, and do not monitor the working conditions on board those vessels. This situation is of a bad effect on both marine environment and worker’s rights on board flag of convenience vessels. Therefore, it is important to cast light on the mechanisms included in the United Nations Law of the Sea Convention 1982 regarding this problem, and to assess their effectiveness.