Since the 1997 Asian financial crisis, East Asia has seen a move toward greater regionalism. The broadening of the ASEAN + 3 dialogue mechanism is representative of increasing linkages forged between Northeast Asian and Southeast Asian states. Still, there is great speculation as to whether these new linkages will lead to the founding of a new. formal, regional institution among the ASEAN + 3 states. Using the ASEAN + 3 framework as the hypothetical foundation for a new institution in East Asia, this paper will use a New Regional Approach analysis to explore South Korea's role in East Asia regionalism, as it compares to Japan and China. Trade, foreign direct investment and official development assistance toward ASEAN states, as well as democracy promotion proclivities will be analyzed. Based on such analysis, it is recommended that South Korea continue to increase economic and political linkages to Southeast Asia, which will enhance South Korean legitimacy as a regional partner and increase South Korea's relative influence in furthering ASEAN + 3 integration.