MAY 12, 2025 – U.S. Marines and Sailors with 3d Marine Littoral Regiment, 3d Marine Division, supported by U.S. Marines with 1st Reconnaissance Battalion, U.S. Soldiers with 25th Infantry Division, and Philippines Marines with Marines Battalion Landing Team 10, concluded the Maritime Key Terrain Security Operations (MKTSO) event during Exercise Balikatan 25 with the retrograde of forces from the Batanes islands to Northern Luzon, May 2, 2025.
The MKTSO event experimented with the Stand-in Force concept by deploying low-signature, light-weight formations to various islands in the Batanes and Babuyan Island chains to rehearse Expeditionary Advanced Base Operations (EABO), test sensing capabilities, and simulate securing and defending key maritime terrain.
The MKTSO served as a dynamic event that put all seven of the Joint Warfighting Functions – Movement and Maneuver, Fires, Intelligence, Sustainment, Protection, Command and Control, and Information – to the test.
Supporting the movement and maneuver of forces from Northern Luzon to various islands in the Luzon Strait were aircraft with the U.S. Air Force’s 39th Airlift Squadron and the U.S. Army’s 25th Combat Aviation Brigade. Utilizing both C-130 Hercules and UH-60 Black Hawks, the U.S. Air Force and Army moved over 200 U.S. and Philippine military personnel and their equipment to the Batanes and Cagayan Islands. For the first time in U.S. Marine Corps history, the newly fielded Navy-Marine Expeditionary Ship Interdiction System (NMESIS) was inserted on Batan Island.
Once inserted, the NMESIS – owned and operated by U.S. Marines with 3d Littoral Combat Team’s Medium-Range Missile Battery – conducted simulated strikes on nearby and passing vessels with the aide of 3d MLR’s Fires and Air Direction Element.
“Walking off the C-130 with NMESIS onto that island was one small step for a Marine, and one giant leap for U .S.-Philippine-delivered sea denial capabilities,” said Col. John G. Lehane, Commanding Officer, 3d Marine Littoral Regiment.
In the Batanes, U.S. and Philippine Marines conducted sensing operations by establishing commercial radars on the islands’ most exposed high grounds in order to identify and observe passing surface vessels and aircraft. A combined force of U.S. and Philippine Marines, Sailors, and Soldiers also conducted civil reconnaissance missions by meeting with local leaders, medical personnel, and their surrounding community members.
U.S. Marines with 3d LCT also learned jungle warfare and skillcraft from their Philippine Marine counterparts during the MKTSO event, thereby aiding in their ability to self-sustain for longer periods of time. Topics of study included water purification methods, as well as the hunting and trapping of local food sources.
Despite being separated by hundreds of miles of rugged terrain and open ocean, the U.S. and Philippine Marines, Sailors, and Soldiers supporting the MKTSO event from the Batanes and Cagayan Islands were commanded and controlled by 3d Marine Littoral Regiment and 3d Littoral Combat Team’s headquarters elements located back on Northern Luzon.
“The ability of 3d MLR to command and control such a diverse and distributed composite of forces during MKTSO demonstrates our unit’s firm grasp on the concepts that are core to U.S. Marine Corps Force Design. We have been building these capabilties for the past two years. Now that we are here, alongside our Philippine partners, 3d MLR has been able to demonstrate to the Combined and Joint Forces our ability to operate within contested littoral zones in order to conduct EABO, support maritime domain awareness, attack enemy maritime targets, conduct expeditionary strike, coordinate air and missile defense, and support operations in the information environment.” said Col. John G. Lehane, Commanding Officer, 3d Marine Littoral Regiment
Although no live-fire was conducted with the NMESIS during the MKTSO, 3d MLR will demonstrate all of its six mission essential tasks during the execution of Balikatan 25. 3d MLR is participating in four of the six Combined Joint All-Domain Operations (CJADO) events, to include the Integrated Air and Missile Defense (IAMD) that concluded on April 27 at Naval Station Leovigildo Gantioqui; the Counter-Landing Live Fire that will take place on May 3 at Aparri; the Maritime Strike that will take place on May 5 at Naval Station Leovigildo Gantioqui and Basa Air Base; and the Maritime Key Terrain Security Operations (MKTSO) event that concluded on May 2 in Northern Luzon.
Balikatan 25 marks the 40th iteration of the longstanding annual exercise between the Armed Forces of the Philippines and the U.S. military. Taking place from April 21 to May 9 across the Philippine archipelago, Balikatan 25 directly supports the ongoing efforts to operationalize the 1951 U.S.-Philippine Mutual Defense Treaty by ensuring tactical proficiency, interoperability, capability development, and improved military-to-military coordination between our forces. The exercise advances our shared commitment to and support for a free and open Indo-Pacific region.
3d Marine Littoral Regiment is a dedicated U.S. Marine Corps unit specializing in amphibious and littoral warfare operations. Stationed on Oahu, Hawaii, and deployed throughout the Indo-Pacific region, 3d MLR is committed to promoting regional security and stability through strategic partnerships and collaborative efforts with Allies and partner nations.
1st Lt Anne Pentaleri
3rd Marine Littoral Regiment