The international regime for the North Sea functions within a complex network of multilateral and regional treaties and institutions, without the existence of a treaty that focuses on the overall protection of the North Sea ecosystem. Nevertheless, a North Sea regime can be identified. This essay shows that that regime has moved from more functional approaches to a more integrated approach. It describes the legal and institutional framework in which the North Sea regime is situated, discusses relevant geographical and geopolitical factors and analyses how the process of change emerged and developed. It concludes that the transition process is about attaining perceptual changes and that in that process law, and rules and regulations, must be regarded as both substantive content, in the sense of standard or rule, and as process, in the sense of procedures for changing or testing the standards and rules.