The Pacific Islands Countries (PICs) constitute an interesting case in terms of the emergence of regional nationalism in the transnational age. As the PICs encounter rising sea levels and the intensification of cyclones, they actively call on the international community to tackle the climate issues in more radical and ambitious ways. While demanding robust climate action from the global community, the PICs have emphasized their plight, highlighting challenges such as climate-induced migration and devastating cyclones. The reproduction of these memories forms a fundamental image of the Pacific communities as victims of climate change. The PICs perceive the international community, especially developed countries, as the perpetrator of climate change. This image of the victim-perpetrator relationship constructs regional nationalism. The PICs’ case shows that this collective regional consciousness is shaped among those who insist on universal collective action against climate change. This chapter scrutinizes climate change narratives in the Pacific region and analyses how their stories are regionally and internally digested and how the victim-perpetrator structure influences the contemporary Pacific regional nationalism. At the same time, PICs have developed cooperation with international communities, including inter-governmental agencies, international companies, and civil societies. This chapter also examines the relationship between the victim-perpetrator structure and the international cooperativism.