Last month, the Okinawa, Japan-based 12th Marine Littoral Regiment stood up the last of its subordinate units, pulling a storied combat infantry battalion into the fold of a modern front-line Marine Corps force in the Western Pacific.
As the second of the Marine Corps’ three planned littoral regiments, the 12th MLR is tasked with operating alongside Japanese Self-Defense Forces if conflict erupts in the region, notably with China. Its primary missions – including protecting naval and maritime forces from adversary missile and drone attacks and striking the adversary, regardless of warfare domain – are largely focused on the regional threat of China.
Since its redesignation in 2023 from the 12th Marine Regiment, 12th MLR has built a formation that includes the 12th Littoral Anti-Air Battalion, 12th Littoral Logistics Battalion, most recently, and the 12th Littoral Combat Team that formed from the infantry units of 1st Battalion, 4th Marines. Its personnel and equipment structures will closely mirror that of the Hawaii-based 3rd MLR, which is aligned with training and partnering with the Philippines.
“None of those battalions will deploy as a singular unit,” Col. Peter Eltringham said Tuesday during a media call from the Pentagon. “We effectively break them apart into a system of systems, a team of teams, to put small units into austere, maritime key terrain.”
The 12th MLR will grow from its approximately 1,300 Marines and sailors to a force of 2,000 by 2027, when the regiment is expected to reach full operational capability, Eltringham said.
Both littoral regiments are part of the Marine Corps’ so-called stand-in force, which under its Force Design concept are deployed and operating within the first island chain. That’s a geographic area immediate to China where military experts expect China’s People’s Liberation Army would maneuver and attack, such as in a scenario to retake Taiwan or contested isles in the South China Sea.
For the 12th MLR, the Marines’ mission will be “to seize and defend maritime terrain, expand joint sensor and [command-and-control] networks and establish long-range precision fires, in support of sea denial and sea control,” Eltringham said. They would operate in the region’s contested maritime space, conducting distributed maritime operations while integrating with allies, partners and the rest of the U.S. joint force.
So the regiment’s training is focused largely on operating in the region and building on their warfighting capabilities across all the warfare domains.
“We operate in small, dispersed but networked formations so we can provide command and control, sustainment, strike and sensing assets,” Eltringham said. “For us, that’s in the Sakishima islands,” he said.
The chain of islands provide space for Marines and sailors “to rehearse maritime domain awareness, and [we] make sure we are employing and combining capability” with their counterparts of the JSDF, he added.
Last summer, during exercise Resolute Dragon 24, Marines with the 12th MLR deployed with the advanced AN/TPS-80 Ground/Air Task Order radar, to Camp Yonaguni, a Japanese Ground Self-Defense Force base on Yonaguni, Japan’s westernmost isle. During Keen Sword 25 in October, they deployed G/ATOR at Camp Ishigaki “to enhance air surveillance and targeting capabilities,” said 1st Lt. Sarah Bobrowski, a regimental spokeswoman.
The year ahead will be another busy one for the littoral regiment, which was 12th Marine Regiment before its redesignation. The 12th Marines was an artillery regiment amd fell under the Japan-based III Marine Expeditionary Force and 3rd Marine Division, but if first formed in the late 1920s as an infantry regiment, led by Lt. Col. Jesse F. Dyer and with various elements under Brigadier General Smedley D. Butler and 3rd Marine Brigade in China. That’s according to the Marine Corps’ 1972 publication, “A Brief History of the 12th Marines.
As fighting expanded in the Pacific theater, 12th Marines reactivated in 1942 under the command of Col. John B. Wilson. Wilson led the regiment through multiple operations, including Bougainville, Guadalcanal, Guam and Iwo Jima. He later was honored with the Marine Corps naming the desert field encampment — Camp Wilson — at Marine Corps Air Ground Combat Center at Twentynine Palms, Calif. Deactivated in 1946, 12th Marines again reactivated in 1952 and multiple elements deployed to combat in Vietnam.
The 12th MLR’s combat team, formed by 1st Battalion, 4th Marines, has a longer and storied history. Formed in 1911, 1/4 first saw action in 1916 in the Dominican Republic, according to its official history, and earned its “China Marines” moniker while operating from Shanghai and the Philippines before the Pearl Harbor attack. The battalion re-formed on Feb. 1, 1944, and fought in the bloody battles of Guam and Okinawa.
In 1965, 1/4 deployed to Vietnam and saw combat through multiple operations in the I Corps region and later joined in evacuations from Vietnam. The battalion deployed aboard Navy ships for Operation Desert Storm in 1990-1991 and fought on the ground during Operation Iraqi Freedom in 2003 and again deployed to Iraq in 2004, 2006 and 2008.
12th MLR’s Strategic Role
Yonaguni and Ishigaki are part of the Sakishima Islands, which fall under Okinawa Prefecture. The islands stretch 60 to 150 miles east of Taiwan and are south of Japan’s uninhabited Senkaku islands that are contested by China and Taiwan.
Their location poses something of a front row seat to activities along the South China Sea and is squarely within the first island chain, where U.S. and allies’ military forces are poised as the stand-in force and deployed there would find themselves inside the weapons engagement zone if conflict erupts with the People’s Republic of China.
The 12th MLR “makes sense given the vulnerability of large, fixed bases to PRC strike. And depending on the dispersal plan, having self-deployable, multi-domain units is beneficial if they can take advantage of the archipelagic environment,” Jeffrey Hornung, a senior political scientist and Japan lead for RAND’s national security research division, told USNI News. “This is because this stand-in force is designed to conduct several critical missions that the Joint Force will require.”
Training and operating in that maritime environment requires clear agreements with Japan that define parameters for U.S. forces and, among other things, the supporting logistics required to respond and support those units in a conflict with China, he said.
“With the intention being to have them operate across the competition continuum, I think the big question will be ‘when’ the MLR can move. There are many regulations and agreements in place regarding what U.S. forces can do outside of their bases and when they can do it,” Hornung said by email. “If one of the benefits of an MLR is its ability to operate in small, scattered locations, that will require agreement by both local authorities and the central government for when U.S. soldiers can do this. Depending on what ‘situation’ Tokyo declares, this movement could be delayed, thereby negating an early mover benefit for the MLR.”
Eltringham said he’s focused on strengthening the MLR’s relationship and interoperability with the JSDF. “We are joint ready, bilateral organizations at our core,” he said. The MLR established a bilateral ground tactical coordination center that’s integrated across warfighting functions, including communications, fires and sustainment.
The regiment continues to build on its capabilities for its two warfighting concepts: expeditionary advanced base operations and littoral operations in contested environments. “When we establish expeditionary advanced bases, we move to those locations, and then we can continue to further distribute [forces] from those advanced bases as we create that cycle of movement and of maneuver,” the colonel said.
Bilateral exercises with Japan, joint training and regular unit-level training – including the recurring Resolute Dragon and Keen Sword exercise series – are building the regiment’s warfighting capabilities. “The challenge is making sure we are doing the timing and the sequencing correctly, through the joint exercise lifecycle … and across the year,” Eltringham said, adding that “we’re getting better and stronger as the months pass.”
The 12th MLR did joint medical evacuation drills and trained with Japanese forces at Camp Yonaguni to build an expeditionary medical response, according to Bobrowski, the regimental spokeswoman. It continues to train regularly with the JSDF she said, and will join them again for the annual bilateral exercise Resolute Dragon 25 later this year.
Layers of Logistics
A conflict with China in the region will challenge the ability of MLRs to support and resupply its small forces dispersed across the region. So commanders are counting on layers of support from aircraft – such as U.S. and Japanese C-130 and C-17 transports and air-delivery drones – and from surface vessels, including autonomous unmanned vessels. “The logistics associated with that are absolutely critical,” Eltringham said.
In a conflict, he said, “the challenge would be whatever their individual job is is going to be complicated by the adversary’s ability to influence it.”
“If they are sensed, then they well may become a target – so the challenges are very real, particularly in a drone-swarm type of scenario or within the weapons engagement zone of enemy theater ballistic missile and things like that,” he added. “I need them to be survivable, I need them to be flexible and I need them to think about and be adaptable to other means.” That might include Marines finding ways to get an Autonomous Low-Profile Vessel, or ALPV, in to bring supplies when another method of delivery isn’t possible, he said.
“What we owe those Marines is the ability to train on that gear and be able to adapt as quickly as possible,” Eltringham said. They might end up “in a situation where we are without communication or without logistical resupply within a period of time. So those Marines have got to be ready to remain sustainable … for prolonged periods of time.”
To get them to think, act and plan for those possibilities, the MLR is focusing training on teaching Marines to work locally, within the island or jungle environment they find themselves in, he said, so they learn to sustain and subsist “until we can get to them.”
Equipping the MLR
As envisioned, littoral units will be disaggregated across a vast maritime region, and the Marine Corps is counting on advanced technologies and systems to give Marines and sailors the warfighting capabilities they need – and across all warfare domains. By dispersing units, Eltringham said, “we can cover more ground. We can create larger sensor networks … and strike-capable networks and ranges.”
To prepare for a potential conflict, the 12th MLR is getting equipped with some of the Marine Corps’ latest advanced gear, including advanced radar systems, anti-ship missiles, and resupply drones. That includes the Navy/Marine Expeditionary Ship Interdiction System, or N/MESIS, which would be employed alongside Japan’s surface-to-surface missile capability. The 3rd MLR has been fielding the system, he said, and “it’s something that we will be receiving over the course of the next couple of months.” The regiment’s 12th LCT eventually will get 18 N/MESIS, Military.com reported last month.
“All of these increase our lethality, our survivability and our sustainability,” Eltringham said. The G/ATOR systems “allow us to hold adversaries at risk and force hard decisions.”
“Technology, however, does not replace the Marine decision-making,” he said, “but it enhances it.”
The MLR’s elements, including the 12th Littoral Anti-Air Battalion, continue to field equipment and gear.
The Marines are focused on fundamental combat fieldcraft and on core technical skills, including air surveillance and early warning, air control, and ground-based air defense. “These are complex skill sets, and our Marines are laying the foundation now so as equipment arrives, we’re ready to employ it effectively,” Lt. Col. Scott Caton, the 12th LAAB commander, said by email.
The battalion is working on plans with the U.S. Navy, Army and Air Force for upcoming joint training, which will “increase significantly in the future,” he said. Marines also are training with the Okinawa-based Marine Air Control Group 18, “reinforcing our integration within the Marine Air Command and Control System and sharpening the edge of our operational readiness.”
The Marine Corps wants its frontline MLR units to be less predictable and less identifiable than its traditional expeditionary forces have been.
“I want them to be small teams. I want them to be hard to find,” Eltringham said. They will be equipped with networked capabilities to collect and share intelligence, conduct and support strikes on targets, and do command and control for their Marines or to support others.
“Success in the littorals requires empowering small agile units so they can be able to make quick decisions at the tactical level,” he added, noting that littoral warfare “is fast, it’s fluid and it’s complicated by multiple factors.” Issues like an adversary’s unexpected actions or a break in communicating with higher command can challenge junior leaders.
It’s important to place trust on subordinate leaders and empower them to take initiative and exploit the adversary’s gaps as they arise, Eltringham said, and ensure they “have the appropriate authorities to be able to execute when they don’t have the ability to communicate safely with higher headquarters or adjacent units.”
A conflict in the contested maritime environment “is all about speed, tempo, adaptation and sustainability,” he said, and ultimately “to force our adversaries to make very, very difficult decisions.”
