China: While China has historically been an ally of North Korea, its relationship with South Korea has strengthened in recent years. However, China's strategic interests and involvement in the Korean peninsula can cause tensions between China and South Korea, particularly regarding North Korea-related issues.
Japan: Japan and South Korea have a complex relationship rooted in historical disputes and territorial claims. While diplomatic relations have improved, ongoing issues such as territorial disputes over Dokdo/Takeshima Islands and differing perspectives on historical events can strain relations between the two countries.