This chapter discusses the future for regionalism and regionalization in East Asia and in Europe by examining possible scenarios in terms of the following three features: Who will integrate what, and how? We start with the recent developments and possible scenarios in East Asia. After an evaluation of existing frameworks, two scenarios are developed—one focused on continued flexible cooperation and a less likely one on more integration in specific areas. For the European Union (EU), also two scenarios are developed, although for this region, we start with the scenario of more integration in specific areas and add to this a second scenario called “the return of the nation-state,” because of the need for flexible cooperation instead of more legal integration. In general, in East Asia, regionalism and regionalization are more flexible than in the EU and Europe. This is related to the concept of “open regionalism.”