The core issue revolves around the Mekong River, a vital waterway for six countries – Thailand, Cambodia, Laos, Vietnam, Myanmar, and China – and a critical factor in regional stability. Water management disputes, driven by upstream dam construction and varying demands for irrigation and hydropower, are escalating tensions. Cambodia’s persistent accusations of Thai diversion of water from the Prek Sah Preaek River, a tributary of the Mekong, remain a significant point of contention. Data released by the Mekong River Commission (MRC) in July 2025 revealed a 12% reduction in water flow compared to historical averages, a trend exacerbated by increased rainfall in the upper Mekong region linked to climate change. This water scarcity has triggered heightened anxieties regarding food security and economic development, particularly for nations reliant on the river’s bounty.
Thailand’s response to this situation is characterized by a carefully calibrated approach. The phone call with Vietnam represented a deliberate effort to broaden Thailand’s strategic partnerships, moving beyond traditional alliances with Myanmar and Australia. Vietnam’s rising economic influence and its own assertiveness within the Mekong region make it a key interlocutor. The reaffirmation of the “Comprehensive Strategic Partnership” is designed to leverage Vietnam’s economic leverage and its potential influence within ASEAN. Furthermore, the Thai government’s public statement regarding a peaceful resolution through existing bilateral mechanisms—specifically, the Joint Commission—indicates a commitment to avoiding escalation, particularly given the unresolved disputes with Cambodia. However, this approach simultaneously reflects a strategic desire to maintain diplomatic space while addressing a mounting external pressure.
The issue of Cambodia’s claims gained further momentum in July 2025, following a leaked internal Thai government report detailing concerns about Cambodia’s obstruction of MRC negotiations. This revelation, picked up by regional media outlets, intensified diplomatic pressure on Thailand and contributed to a downturn in bilateral relations. Moreover, China’s increasing investment and influence in the Mekong region, particularly through its Belt and Road Initiative, adds another layer of complexity. Beijing’s construction of dams and hydropower projects along the upper Mekong has fuelled anxieties amongst Southeast Asian nations, further amplifying existing competition for resources and strategic advantage. According to a report by the International Crisis Group, “China’s strategic footprint in the Mekong has fundamentally altered the geopolitical calculus, placing Thailand in a precarious position requiring delicate navigation.”
Looking ahead, the next six months are likely to be dominated by intensified negotiations within the MRC framework. While a definitive resolution to the water sharing dispute appears unlikely in the short term, the call for a “principled and science-based” approach to water management, echoed by the MRC’s technical committee, offers a glimmer of optimism. Long-term, the situation presents significant challenges. Climate change projections indicate further reductions in Mekong water flows, demanding a fundamental reassessment of water management strategies and potentially leading to increased regional cooperation. Thailand’s ability to successfully balance its relationship with Vietnam, manage tensions with Cambodia, and contend with China’s growing regional influence will determine its stability and influence within the Mekong. The coming decade will require Thailand to become a genuinely multilateral leader, proactively addressing shared challenges related to climate change, water security, and regional stability – a task requiring substantial investment in regional institutions and a willingness to embrace collaborative governance.