25 June 2025
CO25140 | Maritime Patrol Aircraft for Underwater Surveillance in the South China Sea
SYNOPSIS
The proliferation of nuclear-powered ballistic submarines and the importance of strategic anti-submarine warfare in the Indo-Pacific have introduced new risks for Southeast Asian countries, particularly those bordering the South China Sea. Without sufficient anti-submarine warfare capabilities, these states risk becoming passive battlegrounds in great-power undersea competitions.
COMMENTARY
During a Congressional hearing before the Senate Armed Services Committee’s Subcommittee on Strategic Forces, the Commander of the US Strategic Command acknowledged that China has fielded a credible sea-based nuclear deterrent capability, owing to its six Type 09IV JIN-class nuclear-powered ballistic missile submarines (aka SSBNs, which stands for Ship, Submersible, Ballistic, Nuclear). There are no indications that China will stop its progress, with reports indicating the development of the next generation of Chinese SSBNs named the Type 09VI.
However, Beijing is not the only country in the region building up its second-strike capability. India has long sought to design and build indigenous SSBNs, resulting in the construction of its two Arihant-class SSBNs. Other smaller powers have also embraced the boomer – US slang for ballistic missile submarines – bandwagon, with North and South Korea developing their conventionally powered ballistic missile submarines (SSBs) and potentially, SSBNs.
This recent proliferation of boomers has caused a significant shift in the region’s maritime domain by the introduction of strategic anti-submarine warfare (ASW) into regional naval dynamics. As SSBNs are the most survivable, and hence, deadly, part of a country’s nuclear triad, it is only logical that they would become the prime target in a war. Consequently, it has become common practice for a government to deploy its nuclear-powered submarines (aka SSNs, which stands for Submersible Ship, Nuclear-powered) to tail other countries’ SSBNs from the moment they leave their bases and throughout their patrol.
This is an inherently dangerous activity, marked by collisions between British, US, and Soviet boats during the Cold War. However, thanks to the geographical nature of the theatre of operations and the geopolitical sensitivities of the time, these collisions often did not escalate. They were routinely kept from the public eye.
Growing Turmoil Beneath the South China Sea
Strategic ASW in the Indo-Pacific has taken on a markedly different character from the Cold War. No longer confined to the quiet expanses of the North Atlantic and Barents Seas, today’s ASW operations are taking place amid dense traffic and geopolitically contested waters.
This is most evident in the South China Sea, the primary bastion of China’s increasingly potent SSBN fleet. Given its disputed status, any accident in the South China Sea will likely involve multiple parties in the region, making it difficult to cover up an accident quietly. Furthermore, tensions are more likely as countries would feel less secure being unable to efficaciously detect, track, and target enemy SSBNs in the region. Only the US, China, India, Japan, South Korea and Australia have this capability, all of whom have growing strategic interests in the South China Sea.
As there is a significant disparity in ASW capabilities between these countries and Southeast Asian littoral states, some of whom are also claimants to territories in the South China Sea, strategic ASW operations in the region could proliferate and escalate regional geopolitical tensions to a level beyond the control of the claimant states. We saw a preview of this when the USS Connecticut struck a seamount (an undersea mountain) in the South China Sea, sparking Chinese protests. This incident demonstrates how extra-regional actors can cause tensions beyond the control of local states and sideline them.
Strategic Vulnerabilities of Regional Countries
The recent proliferation of boomers and the conduct of strategic ASW by the major powers pose another risk for countries in the region. Unlike Norway, Denmark, Iceland, and the UK, whose maritime backyards hosted risky cat-and-mouse games between the West and the Soviet Union, most Southeast Asian countries bordering the South China Sea lack robust ASW capabilities to detect underwater threats.
This is especially true for Indonesia, whose geographic location between Australia – one of the most probable forward station for any Western submarines in the event of a conflict with China – and the South China Sea means that any submarine traffic between those two regions must pass through its archipelagic waters. The same applies to the Philippines, which lies between the Western Pacific and the South China Sea. As such, Indonesia and the Philippines will be rendered vulnerable by the proliferation of boomers and the increase in strategic ASW operations, as their waters will likely be used as arenas of undersea confrontation without their knowledge.
The Way Forward
Given these challenges, one should not dwell on the idea that this trend of “underwater” developments can be stopped or reversed through multilateral dialogues or a regional forum. That possibility ceased long ago. Instead, efforts should focus on ensuring that maritime countries in the region have the capabilities to surveil their archipelagic waters to prevent them from becoming an arena for undersea confrontation.
However, these countries’ efforts to increase their ASW capabilities are often constrained by their defence budgets. Their limited resources usually preclude them from acquiring what is considered the best counter to submarine threats – a submarine of their own. Nonetheless, this does not mean a country cannot substantially upgrade its ASW capabilities.
For countries with limited defence budgets and vast swaths of waters to cover, such as Indonesia and the Philippines, acquiring a fleet of Maritime Patrol Aircraft (MPAs) with ASW capabilities is an attractive alternative. Though often undervalued compared to submarines, the relatively cheaper cost of MPAs and the tactical advantages of an aircraft over submarines mean that these countries can acquire more ASW platforms, and each can cover a much larger area than a conventional submarine.
By investing in more cost-effective platforms such as MPAs, Southeast Asian countries can quickly strengthen their ASW capabilities without overly stretching their defence budgets. While this will not fully address their lack of ASW capability, the platforms would still provide much-needed surveillance capability, especially considering the MPAs’ ability to bring broadband sensors within detection range of enemy submarines quickly.
An MPA capability would enable these coastal states to better monitor the region’s critical maritime chokepoints and classify – and, if needed, deal with – any underwater contacts silently lurking inside their waters. Otherwise, without an ASW capability, they risk becoming another pawn in the underwater nuclear chess game that the major powers play.
About the Author
Joseph Kristanto is an MSc student in Strategic Studies at the S. Rajaratnam School of International Studies (RSIS), Nanyang Technological University (NTU), Singapore. His areas of interest include maritime security, naval warfare, Indonesia’s defence policies, and the geopolitical dynamics of the Indo-Pacific region.
SYNOPSIS
The proliferation of nuclear-powered ballistic submarines and the importance of strategic anti-submarine warfare in the Indo-Pacific have introduced new risks for Southeast Asian countries, particularly those bordering the South China Sea. Without sufficient anti-submarine warfare capabilities, these states risk becoming passive battlegrounds in great-power undersea competitions.
COMMENTARY
During a Congressional hearing before the Senate Armed Services Committee’s Subcommittee on Strategic Forces, the Commander of the US Strategic Command acknowledged that China has fielded a credible sea-based nuclear deterrent capability, owing to its six Type 09IV JIN-class nuclear-powered ballistic missile submarines (aka SSBNs, which stands for Ship, Submersible, Ballistic, Nuclear). There are no indications that China will stop its progress, with reports indicating the development of the next generation of Chinese SSBNs named the Type 09VI.
However, Beijing is not the only country in the region building up its second-strike capability. India has long sought to design and build indigenous SSBNs, resulting in the construction of its two Arihant-class SSBNs. Other smaller powers have also embraced the boomer – US slang for ballistic missile submarines – bandwagon, with North and South Korea developing their conventionally powered ballistic missile submarines (SSBs) and potentially, SSBNs.
This recent proliferation of boomers has caused a significant shift in the region’s maritime domain by the introduction of strategic anti-submarine warfare (ASW) into regional naval dynamics. As SSBNs are the most survivable, and hence, deadly, part of a country’s nuclear triad, it is only logical that they would become the prime target in a war. Consequently, it has become common practice for a government to deploy its nuclear-powered submarines (aka SSNs, which stands for Submersible Ship, Nuclear-powered) to tail other countries’ SSBNs from the moment they leave their bases and throughout their patrol.
This is an inherently dangerous activity, marked by collisions between British, US, and Soviet boats during the Cold War. However, thanks to the geographical nature of the theatre of operations and the geopolitical sensitivities of the time, these collisions often did not escalate. They were routinely kept from the public eye.
Growing Turmoil Beneath the South China Sea
Strategic ASW in the Indo-Pacific has taken on a markedly different character from the Cold War. No longer confined to the quiet expanses of the North Atlantic and Barents Seas, today’s ASW operations are taking place amid dense traffic and geopolitically contested waters.
This is most evident in the South China Sea, the primary bastion of China’s increasingly potent SSBN fleet. Given its disputed status, any accident in the South China Sea will likely involve multiple parties in the region, making it difficult to cover up an accident quietly. Furthermore, tensions are more likely as countries would feel less secure being unable to efficaciously detect, track, and target enemy SSBNs in the region. Only the US, China, India, Japan, South Korea and Australia have this capability, all of whom have growing strategic interests in the South China Sea.
As there is a significant disparity in ASW capabilities between these countries and Southeast Asian littoral states, some of whom are also claimants to territories in the South China Sea, strategic ASW operations in the region could proliferate and escalate regional geopolitical tensions to a level beyond the control of the claimant states. We saw a preview of this when the USS Connecticut struck a seamount (an undersea mountain) in the South China Sea, sparking Chinese protests. This incident demonstrates how extra-regional actors can cause tensions beyond the control of local states and sideline them.
Strategic Vulnerabilities of Regional Countries
The recent proliferation of boomers and the conduct of strategic ASW by the major powers pose another risk for countries in the region. Unlike Norway, Denmark, Iceland, and the UK, whose maritime backyards hosted risky cat-and-mouse games between the West and the Soviet Union, most Southeast Asian countries bordering the South China Sea lack robust ASW capabilities to detect underwater threats.
This is especially true for Indonesia, whose geographic location between Australia – one of the most probable forward station for any Western submarines in the event of a conflict with China – and the South China Sea means that any submarine traffic between those two regions must pass through its archipelagic waters. The same applies to the Philippines, which lies between the Western Pacific and the South China Sea. As such, Indonesia and the Philippines will be rendered vulnerable by the proliferation of boomers and the increase in strategic ASW operations, as their waters will likely be used as arenas of undersea confrontation without their knowledge.
The Way Forward
Given these challenges, one should not dwell on the idea that this trend of “underwater” developments can be stopped or reversed through multilateral dialogues or a regional forum. That possibility ceased long ago. Instead, efforts should focus on ensuring that maritime countries in the region have the capabilities to surveil their archipelagic waters to prevent them from becoming an arena for undersea confrontation.
However, these countries’ efforts to increase their ASW capabilities are often constrained by their defence budgets. Their limited resources usually preclude them from acquiring what is considered the best counter to submarine threats – a submarine of their own. Nonetheless, this does not mean a country cannot substantially upgrade its ASW capabilities.
For countries with limited defence budgets and vast swaths of waters to cover, such as Indonesia and the Philippines, acquiring a fleet of Maritime Patrol Aircraft (MPAs) with ASW capabilities is an attractive alternative. Though often undervalued compared to submarines, the relatively cheaper cost of MPAs and the tactical advantages of an aircraft over submarines mean that these countries can acquire more ASW platforms, and each can cover a much larger area than a conventional submarine.
By investing in more cost-effective platforms such as MPAs, Southeast Asian countries can quickly strengthen their ASW capabilities without overly stretching their defence budgets. While this will not fully address their lack of ASW capability, the platforms would still provide much-needed surveillance capability, especially considering the MPAs’ ability to bring broadband sensors within detection range of enemy submarines quickly.
An MPA capability would enable these coastal states to better monitor the region’s critical maritime chokepoints and classify – and, if needed, deal with – any underwater contacts silently lurking inside their waters. Otherwise, without an ASW capability, they risk becoming another pawn in the underwater nuclear chess game that the major powers play.
About the Author
Joseph Kristanto is an MSc student in Strategic Studies at the S. Rajaratnam School of International Studies (RSIS), Nanyang Technological University (NTU), Singapore. His areas of interest include maritime security, naval warfare, Indonesia’s defence policies, and the geopolitical dynamics of the Indo-Pacific region.
