Partnership of convenience: Ream Naval Base and the Cambodia–China convergence
While China is pouring resources into Ream Naval Base, the West must continue to engage Phnom Penh to counter Beijing's influence in the kingdom.
- It is unlikely that Ream Naval Base in Cambodia will be a Chinese military base or outpost such as the facility in Djibouti fully operated by the People’s Liberation Army. However, China could gain preferential access to the base or use its facilities there to collect intelligence against other states.
- The Cambodia–China defence convergence is driven by differing motives. Cambodia seeks a partner to modernise its military so it can meet perceived security threats from Thailand and Vietnam, while China wants to expand its political influence and military reach in Southeast Asia.
- New political and military leadership in Cambodia offers Australia and other like-minded partners an opportunity to deepen defence relations with the kingdom to counter China’s influence.
Executive summary
The development of Cambodia’s Ream Naval Base has caused concern in the United States and elsewhere regarding its potential to become a Chinese military outpost. This concern is set to grow as the Chinese-supported upgrade of the base nears completion at the end of 2024. There can be little doubt that China is reinforcing its military presence and influence in Southeast Asia. Yet Western partners have often raised their concerns with Phnom Penh in a counterproductive way, failing to understand the factors motivating Cambodia to seek deeper defence ties with China.
By understanding Cambodia’s threat perceptions and the influence of the kingdom’s domestic politics on its defence and foreign policies, Western partners will be better able to balance China’s influence in Cambodia. This paper analyses the factors leading Cambodia to seek closer defence relations with China, and specifically China’s assistance to modernise Ream Naval Base, along with the access rights that may entail. Its findings are based on fieldwork and interviews conducted by the author in Cambodia and with officials from neighbouring countries in 2024.
Introduction
Cambodia’s growing defence relations with China have caused concern among the United States, Australia, India, Japan, and others. [1] Of particular concern is China’s involvement in upgrading Cambodia’s Ream Naval Base, a project funded by China with construction works undertaken by Beijing firm China Metallurgical Group Corporation. [2]
Ream Naval Base is the only Royal Cambodian Navy (RCN) naval facility with direct access to the sea. The only other RCN base houses the Navy HQ and is located in the capital, Phnom Penh. Before the upgrading works began, Cambodian defence partners such as Japan, Russia, and the United States regularly used Ream Naval Base for joint military exercises with the RCN. [3]
Facing the Gulf of Thailand and located close to southern Vietnam, the base did not attract much global attention until 2019. In July of that year, The Wall Street Journal reported that China and Cambodia had signed a secret agreement allowing China’s military to use Ream Naval Base. [4] This new arrangement was of serious concern to the United States and its partners, as the base’s location could give the People’s Liberation Army Navy (PLAN) a foothold in the Gulf of Thailand and further reinforce China’s military presence in Southeast Asia at the expense of the United States. [5]
Suspicion surrounding China’s intentions regarding the base contributed to the degrading of defence relations between the United States and Cambodia. In 2021, Cambodia refused the US Defence Attaché in Phnom Penh full access to the base. [6] Despite Washington repeatedly raising concerns, Cambodia continued to engage China to upgrade the base. Construction works commenced in June 2022. [7] In April 2024, satellite photos published by the Center for Strategic and International Studies confirmed that Chinese warships have been stationed almost continuously at the base since December 2023. These developments reinforced US suspicions that the PLA would gain exclusive use of a section of Ream Naval Base. [8]
Fieldwork
The findings of this Analysis draw heavily from fieldwork carried out by the author in Cambodia in May 2024, during which he met with and interviewed senior defence officials at the Cambodian Ministry of National Defence. The author was also permitted to visit Ream Naval Base, where he met the base’s leadership group, including the Commander, Rear Admiral Mey Dina.
Interviews and conversations undertaken by the author during his visit, including with government officials, retired politicians, and members of non-government organisations working on strategic issues, enabled him to gain a broader assessment of Cambodia’s threat perceptions and defence policy settings for this paper.
Other data are drawn from open-source materials and documents, along with interviews involving defence and intelligence officials from Thailand and Vietnam. The author is also grateful for the input provided by former and current naval and intelligence officials from other Southeast Asian countries. Most interviewees chose to remain anonymous due to the topic’s sensitivity.
Background
Cambodia’s history is marked by political instability, efforts at rebuilding, and the challenges of dealing with its traumatic past under the Khmer Rouge regime.
From the Cold War until 1999, the kingdom was in a continuous state of conflict. In 1975, the brutal Khmer Rouge regime took power after a bloody civil war. The kingdom was then invaded, and the Khmer Rouge ousted, by its larger neighbour, Vietnam, in December 1978. The Vietnamese military continued to occupy Cambodia until its withdrawal in 1989, as the Cold War drew to an end.
Even then, military conflict continued. The civil war between several rebel forces against the Vietnamese-installed government in Phnom Penh, which Hun Sen subsequently led as prime minister from 1985, continued until the Paris Peace Agreements between the warring parties in 1991. In 1993, Cambodia held its first free and fair elections since the Khmer Rouge era under the supervision of the United Nations. The elections resulted in a coalition government between the two main political factions: the Cambodian People’s Party (CPP), led by Hun Sen, and the royalist FUNCINPEC party, led by Prince Norodom Ranariddh.
In 1997, Hun Sen secured power after overthrowing Prince Ranariddh in a coup. Complete peace returned to Cambodia only in 1999, when remnants of the Khmer Rouge rebel movement surrendered. More recently, between 2008 and 2011, Cambodia was locked in territorial land disputes with Thailand, leading to deadly military clashes.
With limited resources, and sandwiched between two larger and at times hostile neighbours, Cambodia has sought security under the aegis of China. As a result, Beijing has played an increasingly critical role in Cambodia’s military modernisation.
Several factors have influenced the trajectory of this relationship. First, China is not Cambodia’s immediate neighbour, and Beijing has no territorial disputes with Phnom Penh. Second, growing China–Cambodia defence ties have been driven by close links between the two countries’ political and business elites, centred on former prime minister and current President of the Senate Hun Sen, who has ruled the country for nearly 40 years. Third, existing ties have been bolstered by Hun Sen’s regular emphasis on the importance of China as a great power, describing it as Cambodia’s “most trusted friend”. [9]
Upgrading Ream Naval Base
The Royal Cambodian Armed Forces (RCAF) is undergoing a modernisation program primarily driven by Cambodia’s threat perceptions towards its immediate neighbours, Thailand and Vietnam, and to support the development of Cambodia’s marine resources. While the early phase of this modernisation program focused on the army, senior Cambodian government and defence officials emphasised the need for the RCN to be upgraded to defend the country’s maritime border and interests while providing security conducive to developing marine resources. [10]
Maritime challenges from Thailand and Vietnam are the key elements driving Cambodia to modernise the RCN. Phnom Penh and Bangkok are contesting a maritime area of 27,000 square kilometres in the Gulf of Thailand, known as the Thailand–Cambodia Overlapping Claims Area (OCA). The OCA is believed to contain up to 11 trillion cubic feet of natural gas and 500 million barrels of oil. [11] Cambodia’s main maritime concern regarding Vietnam is directed at the latter’s illegal and unregulated fishing operations in Cambodian waters. [12]
The RCN is a small “brown water” naval force lacking the capability to maintain security even within Cambodia’s small exclusive economic zone (EEZ). Although Cambodia has little capacity to protect its maritime domain, its “blue economy” accounts for an estimated 3.2 million jobs and contributed about US$2.4 billion, more than 10 per cent, to Cambodia’s gross domestic product (GDP) of US$18 billion in 2015. [13] In the long term, Cambodia also seeks to exploit contested oil and gas resources in the Gulf of Thailand, where it has discussed joint exploration with Thailand.
Taken together, Cambodia’s sense of inferiority when compared to its more powerful Southeast Asian neighbours and its ambition to develop its marine resources have created a powerful incentive to seek assistance from China for both general military modernisation and in particular the development of its navy. In turn, Beijing may seek to harness Cambodia’s reliance on China in defence matters to advance its military access and presence in Cambodia and Southeast Asia.
Cambodian military leaders see upgrading Ream Naval Base as vital to the RCN’s modernisation agenda. The following table lists some of the construction and upgrading work China has undertaken at the base. [14]
The installation of radars covering Cambodia’s air and maritime domains is particularly important. These radars will enable the RCAF to enhance its maritime domain awareness, detect potential air and maritime threats, and protect commercial shipping calling at its port. While details of these radars are not available, Vietnamese officials suspect that the future Cambodian radar system could also track air activities up to and beyond Ho Chi Minh City in the southern part of Vietnam. [15] In 2022, the RCAF also acquired a Chinese-made KS-1C surface-to-air missile system with a range of up to 50 kilometres. [16]
Another major project on the base is the construction of a new command and control centre enabling the RCN to track and communicate with its vessels operating further at sea. Besides boosting maritime domain awareness, the centre will allow the RCN to better conduct and coordinate naval operations.
Chinese Type 056 corvette at Ream Naval Base on 21 May 2024 (Author’s own image)
A third major project is the construction of larger dockyards and a longer pier in deeper water. While major works by Chinese contractors on the pier have been completed, there are ongoing minor works, and the pier will be handed over to the RCN upon completion. The new pier aligns with the RCN’s plan to acquire larger and more modern vessels to boost its operational capacity. The RCN first announced its intention to purchase modern warships in 2016. [17] In September 2024, the Cambodian Ministry of National Defence announced that China would transfer two newly built Type 056 corvettes to the RCN. [18] However, financing details remain unclear. [19]
China’s interests at Ream Naval Base
Due to Phnom Penh’s financial limitations, Beijing’s support is critical for the Cambodian navy’s modernisation program, particularly for the upgrading works at Ream Naval Base. However, Beijing’s involvement in the project raises several issues that may have a broader impact on regional security dynamics. These include whether the base will fall under China’s exclusive control, the extent to which it could be used for PLA Navy power projection, and whether it will impinge on the security of Thailand or Vietnam.
Exclusive control versus preferential access
China has sought to secure access to port facilities in various parts of the world to protect its sea lines of communication and project military power at greater distances. [20] By funding and providing the labour to upgrade Ream, China will likely gain some form of access to Ream Naval Base. [21] But this could range anywhere from exclusive control to preferential access. China’s PLA base in Djibouti is a prime example of the former, while the deep water port in Hambantota, Sri Lanka is an example of the latter.
In the case of Hambantota, China gained majority control of the port in 2017 through a 99-year lease to a Chinese firm, China Merchants Port Holdings, after Sri Lanka failed to repay its debt. [22] The visit to Hambantota in 2022 by a Chinese-flagged ship, Yuan Wang 5, suspected of carrying out surveillance on Indian ports demonstrated how China could use its access to project military power into distant waters. [23]
However, Hambantota also reflects China’s less-than-firm grip on ports over which it does not have exclusive control. In 2024, reports surfaced that Sri Lanka refused to allow Chinese research vessels to visit its ports or operate within its EEZ for a year after pressure from India and the United States. [24]
Power projection
It is likely that China’s access to and control over Ream Naval Base will fall somewhere between Djibouti and Hambantota, similar to the preferential access afforded to Russia and the United States at Vietnam’s Cam Ranh Bay and Singapore’s Changi Naval Base, respectively. [25] In part, this may be because Ream Naval Base is likely to be of limited strategic value to China as a means to project naval power in the South China Sea. The base’s location in the Gulf of Thailand makes it less important than China’s man-made islands in the South China Sea. [26]
The waters surrounding Ream are too shallow for large warships such as aircraft carriers and supply ships, even after dredging works around the new pier. The new water depth of 8 to 11 metres around the pier is still insufficient for the PLAN’s aircraft carriers and large supply vessels, which appear to have a draft of 10 to 12.5 metres. [27]
Furthermore, Ream is only about 30 kilometres from Vietnam’s resort island of Phu Quoc, where the Vietnam People’s Navy maintains a facility from which Vietnamese forces could easily monitor Chinese naval operations at Ream. In the event of a military conflict over Taiwan or the South China Sea, the region’s two most likely flashpoints, Ream Naval Base would be a less desirable location for Chinese warships than its existing outposts in the South China Sea, which are equipped to host combat aircraft and are armed with anti-ship and anti-aircraft missile systems. [28]
Intelligence gathering
By contrast, the PLA could use Ream Naval Base as an intelligence-gathering post to monitor Vietnamese naval and air activities in the southern part of Vietnam using newly installed radar facilities. Furthermore, the RCN could share information with China, removing the need for PLA personnel to be deployed there. [29] A Vietnamese official pointed out that any Chinese personnel assisting in running new facilities at the base or maintaining Chinese-supplied warships could collect intelligence, thus negating the need to turn the base into a Chinese one. [30]
Entrenching political influence in Cambodia
China has become an essential arms supplier and funding source for Cambodia’s military modernisation efforts. As a result, Beijing expects to grow its political sway in Cambodia as part of an overall strategy to expand its influence in Southeast Asia. [31] Cambodia has been more receptive than other Southeast Asian countries to increased cooperation with the PLA. While China has traditionally used economic means to expand its political influence, it has recently also increased defence engagements in Southeast Asia through military exercises and research exchanges, albeit starting from a low base compared to other major powers. [32] The aid to upgrade the Ream Naval Base in that sense carries significant political value for China by helping entrench its influence in the kingdom. [33]
Ream Naval Base and Cambodia’s security concerns
On the demand side, Cambodia’s military modernisation program, including the upgrading works at Ream Naval Base, is driven by an acute sense of vulnerability towards Thailand and Vietnam. This sentiment is widespread in the kingdom’s diplomatic and defence circles, and even among government critics and opposition figures. [34] As one Cambodian defence official put it: “Thailand and Vietnam will take advantage of us if we are weak”. [35]
Thailand
Cambodia’s territorial disputes with Thailand encompass contested land and maritime areas. Deadly military clashes between the two neighbours took place as recently as 2011 over land border disputes centred on the 900-year-old Preah Vihear temple as well as the Ta Moan and Ta Krabey temples. [36] All three temples are culturally and historically significant landmarks for both countries. Additionally, Cambodia still has unresolved territorial disputes with Thailand in the maritime domain — a potential flashpoint is the 27,000-square-kilometre overlapping claims area in the Gulf of Thailand.
While Cambodia and Thailand have publicly reaffirmed their diplomatic resolve to manage these border disputes, Phnom Penh sees its relations with Bangkok as overly beholden to Thailand’s domestic politics. Thai politicians occasionally stir anti-Cambodian sentiment to gain political leverage domestically, causing Thailand to take a more provocative position against Cambodia regarding land and maritime disputes. [37]
Vietnam
Cambodia also has land and maritime security concerns with Vietnam. The two countries’ land border is more than 1,100 kilometres long, with 15–18 per cent of it still unsettled. [38] This ongoing border dispute, combined with a fraught history of Vietnamese military intervention in Cambodia, plays into strong anti-Vietnamese sentiments in Cambodian domestic politics. The presence of Vietnamese illegal immigrants in Cambodia has been a core campaign issue adopted by Cambodian opposition parties since 1993, when multi-party elections first occurred. [39]
The unsettled land border with Vietnam has led to periodic clashes between Cambodian civilians and Vietnamese security forces. [40] According to Cambodian sources, Vietnamese troops have occasionally encroached and set up camps in disputed border areas, such as in the Cambodian province of Svay Rieng, located just across the border from Vietnam’s Ho Chi Minh City. [41]
Vietnamese and Cambodian political leaders refrain from publicising these border clashes to avoid further inflaming domestic public opinion, especially in Cambodia. Given the anti-Vietnamese sentiment within the broader Cambodian population, the Cambodian government is concerned that local opposition groups could exploit the border dispute, turn the population against the government, and harm economic relations with Vietnam. [42] However, anti-Vietnam sentiment has also been increasingly harnessed and cultivated by the ruling government under Hun Manet and his father Hun Sen to bolster the government's legitimacy.
Illegal and unregulated fishing by Vietnamese vessels is the main security concern in the maritime arena. Vietnamese fishing fleets have long fished in Cambodian waters, and the Cambodian navy has insufficient capabilities to deal with the issue. [43]
Growing Cambodia–China defence ties
The Royal Cambodian Armed Forces (RCAF) is a modest force compared to its Thai and Vietnamese counterparts, operating obsolete equipment and assets. For instance, Thailand and Vietnam operate modern combat aircraft such as American-made F-16s, Swedish-built Gripens, and Russian Su-30MK2 Flankers. The RCAF has no modern combat aircraft. Figure 1 illustrates the quantitative disparity between the RCAF and its Thai and Vietnamese counterparts.
Thailand and Vietnam possess more capable surface warships too, with the latter fielding submarines. By contrast, the Royal Cambodian Navy’s (RCN) few patrol boats are insufficient for protecting Cambodia’s EEZ and maritime interests. At times, RCN personnel have conducted maritime patrols using civilian boats. [44] There are concerns among Cambodian defence officials that larger Thai warships could easily push RCN boats out of the disputed overlapping claims areas. [45]
Furthermore, the RCN’s boats are generally more than 30 years old and not equipped to operate far from the shore. Shore-to-ship communication is severely lacking, and maintenance is an issue because of the age of the RCN’s boats and a lack of replacement parts. Ream Naval Base is not equipped to provide maintenance services to RCN boats. Thus, many of them are sent to shipyards in Malaysia and Vietnam for maintenance, which incurs high costs for the cash-strapped RCAF. To address this shortcoming, China is assisting in constructing a dockyard and repair facilities in Ream. [46]
Financial constraints have also hampered efforts to modernise the RCAF. Since 2006, the Cambodian Ministry of National Defence has planned to set defence spending at 2.7 per cent of GDP. However, Cambodia has not been able to meet this target due to poor government financing and other development priorities. The country had the second-lowest per capita income in Southeast Asia in 2022 (US$1,758), above only that of war-torn Myanmar. With 80 per cent of the annual defence budget going to salaries, little is left to acquire new platforms and equipment and to maintain current inventories. [47] Figure 2 illustrates the disparity of defence spending between Cambodia and its immediate neighbours.
During the 2011 military clashes along the border with Thailand, Cambodia sought military aid from Vietnam, Hun Sen’s one-time backer. Vietnam refused as it did not want to interfere in a border conflict between two Association of Southeast Asian Nations (ASEAN) states. [48] This incident prompted Cambodia to seek military aid elsewhere to strengthen its limited defence capabilities. [49] The United States was not a promising source for such aid, as Washington had halted it a year earlier after Phnom Penh deported a group of Uighurs back to China in December 2009. [50] Cambodia suspended its annual military exercise with the United States in 2017. A year later, Washington suspended all military assistance to Cambodia for the latter’s “suppression of the political opposition”. [51] Military engagement with the United States continued to be minimal when Cambodia was the ASEAN chair in 2022. [52]
Despite US consternation about Cambodia's authoritarian turn, Phnom Penh remains keen to push for renewed defence engagements with Washington as it sees the United States as a critical regional security player. [53] Between 2020 and June 2024, Cambodia conducted nine multilateral exercises involving the United States, and 15 bilateral or multilateral exercises involving China. [54] However, in the absence of other major partners, China remains Cambodia's best bet for the urgent task of modernising its military. China has no territorial disputes with Cambodia, and has offered military assistance no other foreign partner could match. [55] From 2018 to 2023, China accounted for more than 93 per cent of Cambodian military equipment imports (an estimated US$117 million out of US$126 million; see Figure 3).
Cambodia’s next generation
Many Cambodians disagree with Hun Sen’s pivot to China, especially given that the United States and Europe remain far more important export markets for Cambodian goods. They would like to see Cambodia maintain a balance in its foreign and defence policies and worry that its first-generation leaders, who emerged following the Khmer Rouge years and were shaped by military conflicts during the Cold War, are not managing relations with major powers effectively. “Vietnam is more sophisticated than Cambodia in balancing its relations with Washington and Beijing,” one former senior government official commented. [56]
However, Cambodia’s increasingly authoritarian political system allows little opportunity for a decisive change in direction. Former Prime Minister Hun Sen continues to manage Cambodia’s foreign and defence affairs from his position as President of the Senate despite the appointment of his son, Hun Manet, as prime minister. While the West Point-educated Hun Manet may have a different disposition to the outside world, Hun Sen effectively continues to rule the country through parallel power structures. [57]
PLA officials have privately raised concerns that younger Cambodian political leaders led by Hun Manet may shift Cambodia’s foreign policy away from China in the long run. [58] This is a possibility as the influence of first-generation leaders ebbs over time. Next-generation Cambodian leaders, many with a Western education, may decide to broaden Cambodia's diplomatic options and space.
Perceptions are shifting among Cambodian elites. According to surveys of regional elites by the Singapore-based Yusof Ishak Institute (ISEAS), an increasing number of Cambodian respondents are concerned about the impact on their country of China’s growing regional political and strategic influence. There has also been a drop in the Cambodian respondents’ favourable perception of China in recent years. When asked if ASEAN were forced to align itself with one of the strategic rivals, more than half of the Cambodian respondents in the 2023 and 2024 surveys indicated their preference for the United States over China. [59] Domestic public opinion would likely be unsupportive of a permanent or declared Chinese presence in Cambodia, which is also prohibited by the Cambodian constitution. If China were announced or revealed to be exercising unilateral control over parts of Ream Naval Base, there would be a risk of public protests against the government. [60]
Policy recommendations
Chinese military aid to modernise Ream Naval Base is largely driven by Beijing’s broader strategic objective to grow its influence in the kingdom and Southeast Asia. However, geographical limitations, a lack of strategic value, and domestic political constraints in Cambodia will present obstacles to any Chinese efforts to turn Ream into a military base fully under PLA control.
The following policy recommendations will allow Western partners to balance China’s influence in Cambodia, albeit that any Cambodian recalibration will be gradual and likely limited to a more even hedging posture between the major powers.
- The United States and like-minded partners should offer closer security ties to Cambodia. This approach will afford Cambodia’s next generation of leaders more options, especially as the influence of first-generation leaders ebbs away.
- Cambodia–US defence relations will likely remain low-key in the short to medium term, given Washington’s traditional concerns over human rights issues in Cambodia. However, the United States should avoid taking punitive measures against Cambodia, which in the past have driven Cambodia to look for help from Beijing.
- Washington should seek to re-establish defence education programs and combined exercises, among other measures, with the RCAF.
- Australia and others, such as Japan, should maintain defence cooperation with Cambodia to fill the gap created by reduced Cambodia–US defence ties. Australia should focus its assistance on supporting Cambodia’s military modernisation goals and maritime domain awareness capabilities.
- Australia has particular advantages in education. It should expand established programs in this field, including the Australian Command and Staff Course and the ASEAN–Australia Defence Postgraduate Scholarship Program. Targeted aid to young RCAF leaders will strengthen Australia–Cambodia defence relations in the long term as they rise through the ranks.
- External partners should engage Cambodia and read the drivers of its defence policy by first understanding the dynamics of its ties with Thailand and Vietnam, rather than exclusively through the prism of US–China competition.
- Investing in new track 1.5 or track 2 dialogues and developing greater connections between Cambodian and US or Australian think tanks would also help facilitate an improved understanding of Cambodia’s interests and concerns.
