The ASEAN-Plus Three (APT) consists of 10 ASEAN Member States, China, Japan, and the Republic of Korea (ROK). Started in 1997 by way of the convening of an Informal Summit among the Leaders of ASEAN, China, Japan, and the Republic of Korea, the APT platform was institutionalised in 1999 where APT Leaders resolved to strengthen and deepen East Asia cooperation at various levels and in various areas, particularly in economic, social, political and other fields.

Today, the APT remains a cornerstone of East Asian economic integration, contributing to broader regional frameworks such as the Regional Comprehensive Economic Partnership (RCEP). It continues to serve as an engine for promoting resilience, connectivity, and sustainable growth across ASEAN and its Northeast Asian partners.

In 2024, the total two-way trade between ASEAN and the Plus Three countries reached USD 1.2 trillion, whilst Foreign Direct Investment (FDI) from the Plus Three countries to ASEAN reached USD 44.4 billion.