Amphibious Forces

amphibious forces
The advanced bases established by amphibious forces will be used to maintain a line from Japan to the Philippines utilising land-based long-range missiles, unmanned systems, aircraft and ships to conduct both offensive and defensive operations (CSBA)

Amphibious warfare has existed as a pillar of western military strategy since World War II, particularly after the experience of the U.S. Marine Corps (USMC) in the island hopping campaigns in the Pacific. New concepts that have emerged and are currently under development will put amphibious forces at the centre of how the Western powers will meet emerging security threats not just in the grey zone under the threshold of war but in high-intensity conflict as well.

Commentators have long predicted the demise of amphibious warfare with the advent of new technologies and weapons that can threaten and neutralise landing operations in the littoral, but amphibious forces have always been adaptable and remain relevant.

The recent adoption of Anti-Access Area Denial (A2AD) tactics and weapons by Russia and China are attempting to make amphibious forces less relevant. The introduction of long-range anti-ship missiles and sensors, unmanned systems, hypersonic missiles to add to existing air, land, surface and underwater defences makes a large-scale amphibious landing against a well defended coastline an extremely difficult proposition.

To this extent the commentators were right, but a large-scale beach assault such as the invasion of Normandy (Operation Overlord) in France on 6 June 1944  are what many observers still associate with an amphibious attack. However, today’s amphibious forces are extremely flexible and can be utilised for a variety of missions including  different kinds of assault (Falkland Islands in 1982), raids, withdrawals, demonstrations and actions to support to other operations. Variations of these kinds of operations have been present throughout history.

The traditional view of amphibious landings seen here on the beaches at Normandy during World War Two. Future amphibious operations during conflict are likely to be radically different, especially in the Pacific (Wikicommons)


Mature military forces are changing their priorities to meet the developing geo-strategic environment by preparing for a near-peer high intensity conflict, with amphibious forces having a specific role to play in countering the A2AD threat.

In June 2018 the USMC has embarked on a new amphibious warfare concept called Expeditionary Advanced Base Operations (EABO). The EABO Handbook released by the Marine Corps Warfighting Lab, Concepts & Plans Division states that: “EABO creates a more resilient forward force posture that circumvents the efforts and obviates the investments of aspiring peer competitors employing long-range precision fires directed at dislodging U.S. forces dependent upon legacy bases, fixed infrastructure, and large targetable platforms. By enabling persistent presence and a more resilient force posture, EABO offers the opportunity to conduct expeditionary operations to defeat an adversary’s strategy without the requirement to destroy all of his forces.”

To engage China this requires the USMC to occupy undefended islands and atolls in the Pacific and install land-based long-range sensors and weapons that can attack enemy surface and air targets. The range of these weapons will create a bubble around that island stretching hundreds of miles that would be risky for an opponent to enter.

By setting up numerous bases like these in the Western Pacific, the USMC can effectively establish its own A2AD sphere and effectively blockade China. Not only will Chinese military forces be prevented from breaking out into the wider Pacific, its commercial operations and trade will be cut-off. Using these islands will make a significant contribution to the US Navy’s (USN’s) efforts to establish sea control in the approaches to the Western Pacific and with this secured more significant regular forces can be brought to bear. Without these forward bases and EABO, breaking the China’s A2AD barrier from the sea alone will be either impossible or extremely costly. By making amphibious forces a key facilitator towards establishing sea control and blockading the enemy, amphibious warfare has therefore become central to US military strategy.

Although the ideas behind EABO are not new and similar operations were considered by the UK Royal Navy as far back as the 1920s it is a significant departure from the existing USMC concept of operations and the way the service is setup to operate. Since WW2 the central doctrine of the USMC has been manoeuvre warfare, sea-basing and the use of large amphibious ships that (once sea control is established by the USN) can concentrate at a specific point offshore and conduct a landing, either opposed or unopposed, putting troops and equipment ashore at a rapid pace. This is to establish and protect a beach head that can then be used as a transit station for bringing a larger force onto enemy territory for further inland operations.

Instead, in the build up to a crisis, amphibious forces are expected to move rapidly to occupy undefended islands and establish bases close to enemy positions for sea control operations. Large amphibious platforms and aircraft carriers are deemed to vulnerable for forward deployment within the range of enemy A2AD weapons.

It means an extensive overhaul of tactics, training and procedures, the procurement of new platforms and equipment, the re-rolling of existing air, surface and undersea vessels and most importantly much better cooperation and integration with the USN, US Army and USAF. The USMC’s Marine air-ground task forces (MAGTFs), from which the service forms its Amphibious Ready Groups ARGs/Marine Expeditionary Units (MEUs) are optimised for power projection onto land – not sea control.

The most recent US Navy Shipbuilding Plan released in December 2020 has made a start towards putting the USN and USMC on the path towards developing its forces to confront the A2AD barrier. The USN inventory is expected to grow from 305 ships in FY2022 to 405 by 2051. The size of the amphibious fleet of warships is expected to grow from 31 to 62 and a combat logistics force of 31 ships to 69 in the same timeframe. The introduction of a large number of unmanned surface vessels will make up a significant proportion of the expanded fleet inventory.

The reason for a larger number of smaller ships is that the USN needs to become more distributed and has spread out over wider areas to avoid presenting opposing Chinese A2AD forces with a concentration of ships that would be the perfect target for long-range strike weapons. All these platforms would be linked by a resilient multi-domain C4ISR architecture. The USN has developed its Distributed Maritime Operations (DMO) and Distributed Lethality (DL) concepts to disperse the fleet whilst retaining offensive power through the deployment of smaller ‘hunter-killer’ surface action groups (SAGs). This is complementary to the USMC’s EABO concept as the land-based and sea-based assets can work together and has been developed as part of the concept of Littoral Operations in a Contested Environment (LOCE) that aims to fully integrate USN and USMC capabilities to overcome threats in the littoral areas.

Theodore Roosevelt and Makin Island Expeditionary Strike Force
The Theodore Roosevelt Carrier Strike Group transits in formation with the Makin Island Amphibious Ready Group in the South China Sea on 9 April, 2021. Large deployments such as this would not be possible so close to China as the vessels would be vulnerable to strikes from long-range A2AD weapons (US DoD)

The highlights of the Naval Shipbuilding Plan 2020 include the procurement of a new Light Amphibious Warfare (LAW) ship that is designed to rapidly transport new Marine Littoral Regiments (MLR) to the selected EABO islands; light aircraft carriers (CVL) to provide additional air support; Next Generation Logistics Ships (NGLS) to provide more distributed logistics support to forward deployed units; and unmanned vessels (extra-large, large and medium) to act as forward sensors, decoys and even potentially as weapons platforms.

However, the LAW has already attracted criticism in the media as initial concepts from the USN have been deemed insufficient for the role that the ships are expected to undertake – mainly that they are too small, not capable enough with too short a lifespan making them too costly. Up to 35-40 could be acquired and a formal Request for Proposal is expected shortly. Meanwhile options for the CVL include converting the USN’s America-class Landing Helicopter Assault (LHA) ships or developing new designs to succeed the Ford-class carriers.

In terms of other weapons, the USMC needs to get new long-range missiles and launcher platforms into the future Marine Corp structure as organic to its expeditionary units. It needs to become more integrated with the US Army to implement a land-based missile strategy for sea denial.

The outcome of a conflict in the Western Pacific could hinge on which side is able to take and secure islands in the area and best utilise them as part of their defensive and offensive strategy. Whilst China’s amphibious forces are largely focussed on the ability to invade Taiwan the People’s Liberation Army Navy (PLAN) has been developing longer range amphibious capabilities with its new Type 071 LPDs and Type 075 amphibious assault ships that can reach distant islands in the so-called First Island Chain and beyond. It could be a case of who gets there first.

As a result, more capable amphibious forces are also being developed by US allies in North East Asia: Japan, South Korea and Taiwan to support an island-grabbing strategy and prevent China from moving past the first island chain. Japan’s most recent annual defence white paper, published in July 2020, states: “China has relentlessly continued unilateral attempts to change the status quo by coercion in the sea area around the Senkaku Islands, leading to a grave matter of concern. The Chinese navy and air force have in recent years expanded and intensified their activities in the surrounding sea areas and airspace of Japan, and there are cases involving the one-sided escalation of activities.”

Japan’s response has been the modification of the JMSDF’s two Izumo-class (22DDH) helicopter carriers – classed as destroyers locally – to be able to launch and recover the F-35B. This will be useful in forward deploying aircraft to the farthest islands to provide air defence. Meanwhile in March 2018 the Japan Ground Self-Defense Force (JGSDF) established a new Amphibious Rapid Deployment Brigade in March 2018 designed to capture islands in the event of war.

It has 3,000 personnel across three amphibious regiments, combat landing battalions, artillery, reconnaissance, engineers, communications and logistics units. These are to be equipped with AAV7 amphibious assault vehicles, MV-22B Osprey tiltrotor aircraft, 120mm mortars and boats. One major issue is transportation as the existing three Oosumi-class transport ships are unable to lift the entire brigade, additional commercial high-speed ferries are being rented to fill the gap. Replacement ships have not been included in the most recent Japanese defence programme but this may change if the security situation worsens.

BLT 1/1 Marines work alongside JGSDF during Japanese Amphibious Rapid Deployment Brigade’s unit-activation ceremony
The Japanese Amphibious Rapid Deployment Brigade see here deploying from an AAV7 during its activation ceremony at Camp Ainoura in Japan on 7 April 2018. Most recently the ARDB trained alongside the US III Marine Expeditionary Force’s 3D Marine Expeditionary Brigade (MEB) in Yama Sakura 79 – a command and control exercise encompasses large distances using the sea to manouever while establishing expeditionary advance bases in order to occupy key terrain. (USMC)

In what looks like a deployment similar to what an EABO might be like, the JMSDF has already increased its forces stationed on Miyakojima Island part of the Ryukyu archipelago that is part of the First Island Chain and close to Taiwan and south of the disputed Senkaku Islands. The force includes mobile anti-ship missiles, surface-to-air missiles and armoured vehicles. The Izumo-class and the amphibious brigade would be tasked with reinforcing these islands if hostilities break out.

In South Korea the latest Mid-Term Defence Plan (MTDP) released in 2020 signified the intention to procure a light carrier, in a programme known as LPX-II. The new ship design will be based on the existing two Republic of Korea Navy (RoKN) Dokdo-class (LPX-I) amphibious platform docks (LPDs). With a displacement of up to 40,000t LPX-II will have space for F-35B aircraft and helicopters it could inform the development of USN’s planned new CVL. The Dokdo and Marado LPDs each have the capacity for 720 marines and approximately 200 vehicles or Korean Amphibious Assault Vehicles (KAAVs) with two Landing Craft Air Cushion (LCAC) hovercraft to transport them ashore at speed approaching 40kt. There are spots for five helicopters on deck with space for 10 helicopters in total. Also announced in the MTDP is an expansion of the ROK Marine Corps that will receive additional transport helicopters and a new programme for attack helicopters will be initiated. Other items for acquisition include new fast landing ships and the KAAV-II amphibious assault vehicle.

ROK, US Marine forces strengthen relations at Exercise Ssang Yong 2013
Republic of Korea Marine Corps assault amphibious vehicles advance past a smoke screen as their crews execute an amphibious landing at Doksuk-ri Beach in the Republic of Korea during Exercise Ssang Yong 2013, an annual bilateral training exercise in the ROK designed to strengthen combat readiness and interoperability of U.S. and ROK forces. (USMC)

In April Taiwan launched its own domestically built LPD called Yu Shan at the CSBC Corporation shipyard. The vessel is due to enter service with the Republic of China Navy (ROCN) in early 2022. Importantly it includes the capability to launch anti-ship missiles and surface-to-air missiles – a trend that is expected to increase in future amphibious ships to enable improved protection and offensive capabilities. The ship is designed to protect and re-supply Taiwan’s islands in the South China Sea and start to replace the ROCN’s three existing second-hand amphibious ships. Taipei has a requirement for four such LPDs and as they can host Taiwan marines, AAVs, a Chinook helicopter, medium helicopters and landing craft it represents a considerable uplift in capability and a shift away from a strictly main island defensive posture.

The shift towards making amphibious warfare a priority indicates where the decisive actions are expected to be taken in the Indo-Pacific region. The occupation of islands across the Western Pacific and South East Asia and establishment of EABO by the US and its allies will be essential to success if an initial containment strategy and blockade of China is to be effectively achieved. This not only requires the development of the right amphibious force mix and operational doctrine but the ability to network those units and ensure integration with other services.

by Tim Fish