The deep ocean, the largest biome on Earth at over 1 000 metres below the surface of the ocean, holds vast quantities of untapped energy resources, precious metals and minerals. Advancements in technology have enabled greater access to these treasures. As a result, deep sea mining is becoming increasingly possible. To date no commercial deep sea mining operation has taken place, but plans to open a deep sea mine have recently been announced. Our ability to anticipate the impacts of mining is limited by the lack of knowledge about deep sea biodiversity, ecosystem complexity, and the extent of environmental and social impacts from mining operations. As such, it is important that policies guiding mineral extraction from the deep seas are rooted into adaptive management – allowing for the integration of new scientific information alongside advances in technology. Governance mechanisms for international waters and the seabed need to be strengthened. The precautionary approach should be used to avoid repeating instances of well-known destructive practices associated with conventional mining.