Interest in seabed mineral mining has renewed in recent years for various reasons and new offs-hore mining legislation is currently being developed for national and international waters. For this reason, agreement on the meaning of ‘effective protection of the marine environment from adverse effects arising from activities’ related to mining is needed. The International Seabed Authority (ISA) is mandated to manage access to and benefits from the seabed, subsoil and its mi-neral resources in the Area on behalf of mankind as a whole. This legal mandate comprises the development of rules, regulations and procedures for mining-related activities in the Area, which must prevent, reduce and control harm to the marine environment and ensure that such harm does not breach the standard of ‘effective protection’.