Good Faith and Provisional Arrangements in the East Sea: Vietnam’s State Practice and ASEAN Implications

The growing complexity of maritime disputes in the East Sea poses challenges to the multilateral legal order established by the 1982 United Nations Convention on the Law of the Sea (UNCLOS). This study analyzes how Vietnam operationalizes the principle of good faith (Article 300) and provisional arrangements (Articles 74 and 83) to manage maritime disputes and promote regional stability. Integrating normative doctrinal inquiry with qualitative analysis of State practice, the research evaluates Vietnam’s bilateral agreements concerning joint development, maritime delimitation, and fisheries cooperation. The findings demonstrate that Vietnam has consistently utilized institutional and civilian frameworks to transform abstract obligations of conduct into functional maritime cooperation. State practice reveals the efficacy of equitable provisional mechanisms, including joint resource management and adjusted boundary configurations in disputed areas. Furthermore, Vietnam aligns its jurisdictional claims with geoscientific parameters and the regime of islands under Article 121(3), as evidenced by its diplomatic notes and submissions to the Commission on the Limits of the Continental Shelf (CLCS). Consequently, institutionalizing regional mechanisms under UNCLOS Article 123 provides a rules-based framework for preserving stability and ecological cooperation in semi-enclosed seas.