The technical case for subsea power cables connecting Southeast Asia's electricity systems has been established, with a focus on governance arrangements evolving alongside regional electricity integration. ASEAN's cross-border electricity ambitions will require stronger regional planning, cost allocation approaches, and coordination across the maritime domain. The region aims to more than double its interconnector capacity by 2040, benefiting from abundant renewable energy resources and the potential to reduce fossil fuel imports through subsea cables. Addressing gaps in regional planning, cost allocation, and navigating territorial waters will be crucial for successful implementation of cross-border subsea interconnection projects in ASEAN. The article discusses the need for governance arrangements to support the development of cross-border energy infrastructure in the ASEAN region, particularly focusing on the ASEAN Power Grid Generation and Transmission Planning function. It highlights the importance of coordination in planning, regulation, financing, and maritime governance for the success of subsea power cable development, drawing lessons from Europe's experience in evolving governance frameworks for energy infrastructure. The ASEAN region already has foundational institutions in place, such as the ASEAN Centre for Energy, HAPUA, and the APGCC, but there is a need to strengthen governance arrangements to support regional electricity integration.