The COVID-19 pandemic has left international cooperation and liberalistic values in crisis. As liberalism’s downfall is widely discussed, international collaborations like the European Union are criticised for their inability to operate adequately during the pandemic. The four examples in this paper are middle power countries (South Korea, Japan, Taiwan, and Singapore) in terms of economic scale and influence. The purpose of this study was to uncover possibilities for and limitations of these middle powers within international cooperative efforts during and after the pandemic. The unknown factor is the path the post-pandemic world will follow. Will nations focus on independent survival? Or will international cooperation shape the new world? Globalisation already seems to have progressed too far for the national egoism of the great powers to prevail. Even if face-to-face is replaced by virtual and offline meetings move online, the social nature of humans remains unchanged, and international cooperation remains valid. The four middle power countries in Asia, which are included among the most economically successful countries, are important to international society based on their relatively excellent quarantine performance. What is important in the diplomacy of middle power countries is not traditional security and hard power but the soft power of international law, human rights, health security, and international cooperation.