Abstract This paper presents procedural, policy, and legal considerations that states may encounter before and after ratifying the BBNJ Agreement, with a focus on its marine genetic resources (MGR) provisions. It briefly examines the behaviours of parties to the other two previously ratified implementing agreements to the United Nations Convention on the Law of the Sea, as well as some ratification lessons learnt from other relevant treaties. The other three ‘pillars’ of the BBNJ Agreement sit on well-established foundations of national and international law. However, as discussed here, the legal foundation of the fourth pillar, MGR, is less well established nationally or internationally, and much remains to be determined. Therein, the BBNJ Agreement represents a significant advancement of international law. However, the reality is that most parties will not adopt all the necessary new legislation prior to their ratification, nor can they, because many of the MGR provisions are as yet still unclear. States are therefore likely to choose a progressive approach, ratifying the Agreement to signal commitment while gradually developing the legal framework necessary for full compliance, as well as policies to guide its implementation.