The dynamics of diplomatic relations in Southeast Asia in 2023 reflect growing geopolitical complexity, influenced by various local and global factors. ASEAN countries unite to address regional challenges such as climate change, maritime security and external influences. Diplomatic initiatives, high-level meetings and multilateral forums are the main focus in increasing cooperation between member countries. One of the main issues is China’s increasing influence. With the Belt and Road Initiative (BRI) project, China is strengthening economic relations with ASEAN countries through infrastructure investment. Malaysia and Indonesia, for example, have signed several investment agreements with China, which have had a positive impact on their economic growth. However, this dependence also creates challenges to national sovereignty and security, prompting increased cooperation with other countries such as the United States and Japan to create a balance of power. In the field of maritime security, tensions in the South China Sea continue to be an important issue. ASEAN seeks to maintain stability and encourage dialogue through the Declaration on Conduct in the South China Sea. Meetings between ASEAN and Chinese foreign ministers this year showed progress, although differences of opinion still exist. The bilateral agreement between the Philippines and the US, which strengthens the US military presence in the region, is increasingly complex when viewed from the perspective of regional tensions. Climate change is also a major concern, with ASEAN committed to achieving the targets set in the Paris Agreement. Countries such as Vietnam and Thailand are starting to implement ambitious renewable energy policies. The 2023 ASEAN Summit was held to discuss concrete steps in mitigating and adapting to climate change, emphasizing the importance of cross-country cooperation to achieve sustainable goals. Diplomatic relations in Southeast Asia are also influenced by the domestic dynamics of each country. For example, elections in Thailand and Malaysia in 2023 are of interest, as the results could influence their foreign policies. Predictions suggest that the victory of pro-ASEAN parties in both countries could strengthen collaboration with neighboring countries, supporting economic and social integration. From a trade perspective, ASEAN targets to strengthen the ASEAN Economic Community (AEC) through reducing tariffs and increasing investment. This integration process will rely heavily on technological support and innovation that can bring lower production costs and high efficiency. At the multilateral level, ASEAN plays an active role in various international organizations, including the East Asian Cooperation Forum and APEC. ASEAN countries use this forum to strengthen solidarity in facing the global crisis and promote relevant common agendas such as security, trade and health. Overall, Southeast Asia in 2023 shows the dynamics of diplomatic relations that are more complex and interdependent. Through closer cooperation, countries in this region are trying to create stability and prosperity, even amidst tensions in power play between global powers. It is hoped that strengthening cooperation and finding joint solutions will have a positive impact on society and the economy throughout Southeast Asia.