Historically, the IMSZ has been characterized by overlapping territorial claims, particularly concerning the Spratly and Paracel Islands. While Thailand’s position is largely defensive, rooted in its maritime security concerns and the protection of its valuable fishing grounds, the zone’s strategic importance has dramatically increased with the recent discovery of significant undersea mineral deposits – an element driving considerable naval modernization and reinforcement of existing claims by several nations. Data released by the International Seabed Authority in late 2024 indicated estimated reserves of rare earth elements within the IMSZ exceeding $3 trillion – a figure that has undeniably sharpened strategic competition.
The core stakeholders in this evolving landscape are multifaceted. Thailand, under Prime Minister Narongchai Suksa, has maintained a relatively neutral stance, prioritizing its national security and economic interests – largely centered on fisheries and tourism – while simultaneously strengthening its naval capabilities through the acquisition of advanced surveillance technology and maritime patrol vessels. Myanmar, weakened by internal conflict and increasingly reliant on China’s support, presents a complex challenge. Its naval forces are ostensibly tasked with maintaining maritime order, but their actions are often viewed with suspicion by Thailand and Vietnam. Vietnam, heavily invested in fishing and seeking to assert its sovereignty over disputed islands, represents a direct counterweight to China’s growing influence in the region. China’s People’s Liberation Army Navy (PLAN) maintains a robust presence in the IMSZ, conducting increasingly frequent naval exercises and deploying advanced warships – a move interpreted by Thailand and others as an attempt to expand its sphere of influence and challenge existing maritime order. According to a report by the Center for Strategic and International Studies (CSIS) in December 2025, “China’s naval deployments in the IMSZ have increased by 35% over the past two years, directly correlating with the heightened competition for seabed resources.”
“The increased naval activity, particularly by China, isn’t simply about asserting territorial claims,” stated Dr. Anya Sharma, a senior maritime security analyst at the Institute for Global Studies. “It’s a demonstration of power and influence, a testing ground for new technologies, and a projection of capabilities designed to shape the regional security architecture.” The Thai government has responded with diplomatic initiatives, primarily through the ASEAN framework, and increased naval patrols within its designated EEZ. Furthermore, Thailand has begun to subtly align itself with Australia and India, seeking strategic support and leveraging their naval expertise.
Recent developments in the last six months have intensified the situation. In November 2025, a Thai Coast Guard vessel reportedly intercepted a Chinese fishing vessel suspected of illegal seismic surveying within Thai territorial waters, leading to a sharp escalation in rhetoric between Bangkok and Beijing. Simultaneously, Vietnam conducted a series of joint military exercises with the United States Navy near the disputed Paracel Islands, further raising tensions. Moreover, a leaked internal document from the Thai Ministry of Defence highlighted concerns about potential Chinese submarine operations in the IMSZ.
Looking ahead, the next six months will likely see a continuation of the current dynamic – increased naval deployments, heightened surveillance, and sporadic incidents at sea. Long-term, the potential for miscalculation and escalation remains a significant risk. The competition for seabed resources could trigger a protracted naval arms race, further destabilizing the region. Furthermore, the involvement of external actors, such as the United States, Australia, and India, could exacerbate the conflict. “The key challenge for Thailand,” commented Professor David Lee of Chulalongkorn University’s Political Science Department, “is to maintain a delicate balance between asserting its national interests, navigating the complexities of ASEAN diplomacy, and avoiding being drawn into a larger regional confrontation. Success hinges on consistent strategic communication and proactive engagement within the multilateral framework.”
Within the next five to ten years, the situation could evolve into a more defined maritime security environment. A potential outcome involves the creation of a regional maritime security framework, facilitated by ASEAN, with the involvement of key external actors. However, this scenario remains contingent upon a willingness from all parties to engage in constructive dialogue and address the underlying causes of the conflict, primarily the competing claims over seabed resources. Alternatively, the ongoing competition could lead to a more fragmented and contested environment, with increased risk of incidents and potential for broader regional instability. The strategic implications of this evolving landscape are significant, demanding careful monitoring and nuanced diplomatic strategies. The question remains: can the international community effectively manage this increasingly complex and potentially dangerous situation, or will the shifting sands of the Indochinese Maritime Security Zone ultimately reshape the geopolitical landscape of Southeast Asia?