Six categories of unconventional or informal law-making are identified, focusing on instruments that are characterised by informality with respect to actors, processes or outputs but which are nevertheless normative in purpose and effect. This chapter briefly considers the role played by these instruments in developing and implementing the law relating to area-based conservation and its relationship with formal law. The chapter concludes with a short analysis of the potential impact of a new formal instrument, the international legally binding instrument under the 1982 United Nations Convention on the Law of the Sea (LOSC) on the conservation and sustainable use of marine biodiversity beyond national jurisdiction (the ILBI), on current and future informal or unconventional law-making processes related to area-based conservation.