The United Nations General Assembly (UNGA) resolution1 welcoming the Advisory Opinion of the International Court of Justice (ICJ)2 and its recommendation that the UK address the issues raised by the incomplete decolonisation of Mauritius, with particular reference to the Chagos Archipelago, raises a number of issues, including the current and future status of the marine protected area (MPA) that the UK declared around the islands in 2010, which is the focus of this chapter. Following an introductory section on the context of the MPA as a conservation measure, and in particular the MPA around Chagos, this chapter considers, firstly, the proposition that the ICJ Opinion marks a change in the relationship between former colonial powers and those countries which were colonies or remain overseas territories, and often fall into the category of less or least developed states. While the Opinion might be seen as a progressive step in the context of marine protection, it is suggested not only that there is still an inequality of arms and that overseas territories and former colonies may be vulnerable players in the race to establish ‘blue’ credentials but also that the new world order is marked by the increasing influence and power of non-state entities, particularly environmental lobby groups, who may be less accountable than states. Secondly, and linked to the first, the chapter considers that the right to self-determination being upheld in the Opinion may not be all that it seems. This is particularly so in respect of the oceans and the resources therein, where the absoluteness of state sovereignty is being increasingly diminished as a result of international obligations to protect the global commons and the biodiversity of the oceans. Thirdly, and again linked to the previous two, while the Opinion was largely concerned with past events, the future international legal order is changing as a result of proposals to manage areas ‘beyond national jurisdiction’: a proposal which seeks to extend international regulation aimed at protecting the marine environment in new directions, possibly with even greater use of MPAs. The chapter concludes with speculation as to the future significance of the Chagos MPA as regards the various interested parties and, closely related to this, the lives of Chagossians wanting to return to the archipelago.