The Thailand Royal Government and regional watchers are monitoring Beijing's strategic intentions toward Cambodia after Chinese President Xi Jinping this week pledged China's willingness to establish a formal security partnership with Cambodia, a move that could reshape Southeast Asia's balance of power and test Thailand's own hedging strategy in the region.
Why This Matters
• Deepened security alignment: China has expressed its willingness to formalize defense cooperation with Cambodia at a time when U.S. influence in Southeast Asia remains contested, potentially complicating Thailand's position as it balances ties with both powers.
• Economic interdependence: Cambodia currently relies on China for more than 70% of foreign direct investment, a dependency level that raises questions about sovereignty and economic resilience across ASEAN.
• Transnational crime cooperation: Xi pledged joint action on cross-border challenges, with emphasis on combating online gambling and telecom fraud syndicates — issues that have directly affected Thailand, where thousands of citizens have been trafficked to scam compounds along the border.
• Regional stability calculus: With Indonesia seeking to remain non-aligned and the United States attempting to re-engage Cambodia through trade and military exercises, Beijing's pledge signals its determination to strengthen ties with its closest regional partner.
From Trade Partner to Security Ally
The pledge came during a Friday meeting in Beijing between Xi Jinping and Hun Sen, the longtime former prime minister who now serves as president of Cambodia's Senate. Despite stepping down from the premiership three years ago in favor of his son, Hun Manet, Hun Sen remains the key architect of Cambodia's foreign policy and is treated by Beijing as a trusted "old friend" — or laopengyou in Mandarin, a term reserved for allies whose loyalty has been tested over decades.
Xi framed the security partnership as a natural evolution of the two nations' "comprehensive strategic partnership," emphasizing that the international and regional landscape was experiencing "complex and profound changes." He praised Hun Sen's efforts to combat transnational crime and pledged joint action to eliminate what he called "malignant tumors" — a reference to cross-border scam operations that have plagued the Mekong subregion.
For Hun Sen, the meeting was an opportunity to reaffirm Cambodia's adherence to the One China principle and support for Beijing's stance on Taiwan reunification. He also expressed gratitude for China's backing of the Cambodian People's Party and its chosen development path, language that underscores the political dimension of the relationship.
Existing China-Cambodia Defense Cooperation
While Xi's pledge to establish a formal security partnership suggests deeper future cooperation, the specific framework has not been publicly detailed. Currently, China and Cambodia already maintain several defense and security arrangements including:
• Joint military exercises: The annual Golden Dragon drills, which began in 2016, continue to be conducted. Cambodia recently received a Type 056C corvette from China, bolstering its limited naval defense capabilities.
• Intelligence sharing and law enforcement: Both sides currently cooperate on cybersecurity, anti-money laundering, and efforts against online gambling and telecom fraud networks — an issue of direct concern to Thailand, where victims have been lured or trafficked to compounds in Sihanoukville and along the border.
• Defense procurement and training: China has emerged as Cambodia's primary arms supplier, providing hardware, training, and logistical support, effectively replacing the role once held by the United States before military ties were suspended in 2017.
• Strategic consultation mechanism: In April, Beijing and Phnom Penh launched their first "2+2" dialogue involving foreign and defense ministers, creating an institutional platform for coordinating regional security policy.
Impact on Thailand and Regional Dynamics
Xi's pledge of a future security partnership with Cambodia carries several implications for Thailand, a country that has historically maintained pragmatic ties with both Washington and Beijing.
Strategic hedging becomes harder: As Beijing seeks to deepen its security alignment with Cambodia, Thailand may face intensified pressure from both sides to clarify its own strategic preferences. The Thai military has conducted joint exercises with both the People's Liberation Army and U.S. forces, but a tightened China-Cambodia relationship could complicate that balancing act.
Border security and crime: The emphasis on transnational crime cooperation is potentially beneficial for Thailand. Thousands of Thai nationals have been trafficked or deceived into working for scam syndicates in Cambodia, particularly in Sihanoukville, which became a hub for Chinese-funded casinos and related industries before a 2019 online gambling ban led to an economic bust. Coordinated enforcement could reduce the flow of victims and dismantle networks operating along the Thai-Cambodian border.
Economic spillover: China accounts for roughly 40% of Cambodia's external debt and over 70% of approved FDI in recent years. Major infrastructure projects — including the Phnom Penh-Sihanoukville Expressway, the Siem Reap-Angkor International Airport, and the Funan Techo Canal — have been financed largely by Beijing. If this economic model proves sustainable, it may offer lessons for Thailand, which is itself a significant recipient of Chinese investment. If it proves fragile, the spillover effects — including debt distress or political instability — could affect Thailand's border provinces and trade corridors.
ASEAN cohesion: The security pledge underscores divisions within ASEAN on how to engage with China. While Cambodia embraces a close partnership, Indonesia and the Philippines have taken more cautious or confrontational stances, particularly regarding the South China Sea. Thailand, as a founding member and traditional bridge-builder within ASEAN, may find it increasingly difficult to maintain consensus on regional security issues.
U.S. Response and the Return of Military Engagement
The United States has watched the China-Cambodia relationship with mounting concern, particularly regarding the expansion of Ream Naval Base on Cambodia's southern coast, where satellite imagery has shown the construction of a pier capable of docking large warships. Washington has accused Phnom Penh of allowing a de facto Chinese military presence, a claim Cambodia denies.
In response, the U.S. has attempted to re-engage. It lifted a 2017 arms embargo and resumed military exercises, albeit on a limited scale. More significantly, Washington signed a reciprocal trade agreement with Cambodia in late 2025 that includes provisions on investment facilitation, intellectual property protection, and alignment with U.S. sanctions policy — terms that could constrain Cambodia's room for maneuver with Beijing.
Analysts view the agreement as part of a broader U.S. strategy to limit China's strategic advantages in the region, though its practical impact remains uncertain given Cambodia's deep economic dependence on Chinese capital.
Indonesia's Independent Path
Indonesia, Southeast Asia's largest economy and a key player in ASEAN, has taken a different approach. Jakarta maintains what it calls a "free and active" foreign policy, seeking to avoid entanglement in U.S.-China rivalry while deepening economic ties with Beijing. China is Indonesia's largest trading partner and a major investor in mining, manufacturing, and infrastructure.
At the same time, Indonesia has pushed for the completion of a Code of Conduct for the South China Sea and expressed concern about Chinese assertiveness in disputed waters. Jakarta's ability to navigate these tensions without alienating either side offers a potential model for Thailand, though the two countries face different geographic and political constraints.
The Economic Foundation of the Partnership
China's relationship with Cambodia is built on an economic foundation that has reshaped the country over the past decade. Chinese investment drove GDP growth averaging 7% annually before the COVID-19 pandemic, with per capita income rising sharply. Major projects have modernized logistics networks and connected Cambodia to regional supply chains, particularly under the Belt and Road Initiative.
Yet this dependence has a downside. The 2019 online gambling ban led to a sharp downturn in Sihanoukville, leaving behind abandoned buildings and unemployment. Real estate prices surged and then collapsed, displacing local communities and raising concerns about environmental damage. Critics also argue that the benefits of Chinese investment have not been evenly distributed, with local populations often sidelined.
The level of reliance — 40% of external debt, over 70% of FDI — leaves Cambodia vulnerable to shifts in Chinese policy or economic conditions, a risk that resonates in Thailand, where policymakers are keenly aware of the dangers of overdependence on any single partner.
What This Means for Residents
For people living in Thailand, Beijing's pledge to establish a deeper security partnership with Cambodia is more than a diplomatic announcement. It has practical implications:
• Reduced trafficking and scam risks: If cooperation on transnational crime proves effective, it could lead to the rescue of Thai nationals trapped in scam compounds and the dismantling of networks that have defrauded thousands of people across the region.
• Border stability: A more closely aligned Cambodia could mean more predictable relations along the border, or it could mean increased military activity and strategic competition that complicates cross-border trade and movement.
• Economic model lessons: The trajectory of Chinese investment in Cambodia — both its successes and failures — offers a case study for Thailand as it navigates its own infrastructure and development needs.
• Strategic pressure: As Beijing works to formalize its security partnership with Cambodia, Thailand may face intensified lobbying from both Beijing and Washington, potentially affecting defense procurement, trade policy, and regional diplomacy.
Xi's pledge this week to establish a formal security partnership with Cambodia marks an important step in an evolving relationship. For Thailand, the challenge is to manage the implications of that transformation while preserving its own room for maneuver in an increasingly polarized region.
