It might be argued that there is no such thing as ‘environmental law’ in the singular, as there are a great many laws which govern human interaction with the environment, ranging from the control of vehicle emissions and the disposal of household waste to the specification of fishing nets, the permitted size of catches, and the registration of vessels. These laws are found not only in legislation but also in private law actions, such as nuisance. This plurality is found in all jurisdictions but in the Pacific region legal pluralism denotes legal systems in which state law – in various forms – exists alongside non-state law, notably customary law. This relationship can be complementary or conflictual. When considering the regulation of human activities that have environmental consequences, it is therefore important to take into account these legal pluralities, not only to ascertain the current legal framework but also when considering possible legal approaches to current or future issues. This chapter adopts a pan-Pacific comparative approach which examines how legal pluralism is or could be used to address environmental concerns focusing in particular on the blue-green environment of the region.