The  Ayeyawady-Chao Phraya-Mekong Economic Cooperation Strategy (ACMECS), a regional cooperation framework involving Thailand, Cambodia, Laos, Myanmar, and Vietnam, was revived in 2018 in part to provide its members with an alternative source of funding to enhance connectivity in mainland Southeast Asia. In the meantime, global powers such as China and the US, as well as emerging economic players in Asia like Japan, South Korea, and India, have actively engaged with the Mekong Region through various sub-regional initiatives, thereby exerting influence in the region. Within an area congested with multilateral frameworks, overlapping agendas and an abundance of funding, ACMECS faces formidable challenges ahead to stay relevant.