As the popularity of deep-sea mining beyond national jurisdiction grows amongst the international community, so does the need to assess whether or not humanity is moving too fast into something unknown and if the application of the Precautionary Principle is in order. Throughout this thesis we analysed the impacts of this activity and the evolution of its legal framework. We also focused on the Precautionary Principle, its core elements and determined whether or not there was cause for applying it to deep-sea mining. We found that there is, in fact, cause and that this Principle has already been included in some aspects of the legal framework of deep-sea mining beyond national jurisdiction. However, this inclusion is still insufficient and in order to build a legal framework based upon the Precautionary Principle, some necessary measures are still missing.