The paper tries not to portray the details of these various economic co-operations in the Asia Pacific. Rather, it tries to discuss general progress and development of regional economic co-operations in East Asia, especially in Southeast Asia-as part of Asia's response to and consequences of globalization in this particular region. Further more,it also discusses possible road maps for a more coherent regional co-operation, its challenges and opportunities and in particular its implications on Japan. It is a widely believed that Japan should-and is expected to promote co-operations in Asia as a means to revive and revitalize regional economy, thus, keeping Japan as one of the most important economic dynamos of the region, and the world