U.S. Marines Test New Unmanned Surface Vessel for Littoral Explosive Threat Detection.

The U.S. Marine Corps has tested an Unmanned Surface Vessel designed to detect and investigate explosive threats across contested littoral zones, according to details released by Portfolio Acquisition Executive Marine Corps on September 15, 2026. The vessel is part of the Littoral Explosive Ordnance Neutralization system, or LEON, which aims to keep explosive ordnance disposal teams farther from mines and other hazards that could block amphibious access and restrict movement ashore.

LEON combines surface, underwater, ground and diver-operated capabilities to locate, confirm and mark explosive hazards from shallow water through the beach zone. By shifting high-risk reconnaissance toward unmanned platforms, the system could improve force protection while helping Marines identify safer routes for amphibious operations in mined or heavily contested coastal environments.

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The U.S. Marine Corps has tested a new unmanned surface vessel at Camp Pendleton to detect and investigate explosive hazards across contested littoral environments while reducing risks to explosive ordnance disposal personnel (Picture Source: Portfolio Acquisition Executive Marine Corps)

On September 15, 2026, Portfolio Acquisition Executive Marine Corps detailed a significant step toward expanding the Marine Corps’ ability to detect, investigate and address explosive hazards across contested littoral environments. Testing at Camp Pendleton placed an Unmanned Surface Vessel at the center of the emerging Littoral Explosive Ordnance Neutralization, or LEON, System of Systems. Designed to increase standoff for explosive ordnance disposal personnel, the capability could extend Marine sensing and communications from shallow water to the beach while reducing exposure to potentially lethal hazards.

The importance of LEON extends well beyond conventional explosive ordnance disposal. Littoral zones are among the most demanding environments for an expeditionary force, where mines, unexploded ordnance and other obstacles can restrict access, delay movement and expose personnel before follow-on forces can maneuver effectively. LEON is being developed to give Marine EOD technicians greater standoff while confirming and marking hazards and obstacles from very shallow water through the beach zone. The System of Systems consists of five capability increments: a Remotely Operated Vehicle, diver equipment, an Unmanned Underwater Vehicle, an Unmanned Surface Vehicle and an Amphibious Unmanned Ground Vehicle. Rather than relying on Marines to physically approach every suspected hazard, the architecture is intended to combine multiple robotic capabilities to support safer reconnaissance and explosive-hazard operations.

At the center of the latest evaluation is a commercial Unmanned Surface Vessel equipped with autonomous navigation and a significant sensor and communications payload. According to Portfolio Acquisition Executive Marine Corps, the USV incorporates sonar, Forward-Looking Infrared cameras, Line-of-Sight communications and acoustic communications. Sonar provides an important capability for searching below the waterline, while FLIR supports observation and situational awareness around the surface operating environment. The combination of line-of-sight and acoustic communications is particularly relevant because it gives the system different means of maintaining connectivity across the surface and subsurface portions of the mission. Instead of functioning simply as a robotic search vessel, the USV is being developed as both a sensor platform and an information link for the wider LEON architecture.

That networking function could ultimately prove as important as the USV's own search capability. Marine Corps officials said the vessel will primarily enable other LEON systems to operate below the surface, locate and identify potential hazards, and relay information back to the surface for real-time updates. As the fourth increment of LEON, the USV is also intended to provide a Mobile Gateway Buoy communications capability. Operationally, this could allow Marine EOD personnel to position a persistent surface communications node above underwater systems while remaining farther from the immediate hazard. By linking submerged platforms with operators and providing updated information on suspected threats, the USV could help transform individual robotic systems into a more interconnected EOD reconnaissance network. The Marine Corps' stated objective is clear: enable maneuver by identifying safer routes for transit through the littorals.

Endurance further strengthens the operational value of unmanned systems in this mission. Marine Corps officials said such systems can conduct missions for upwards of 14 hours, cover large sections of the littoral environment and require relatively limited manpower for monitoring. During the Field User Evaluation, Marines received hands-on instruction in waypoint navigation, target deployment and location verification before testing the USV on the water. System engineers from the Explosive Hazard Defeat Team and EOD technicians from 7th Engineer Support Battalion spent two weeks evaluating the platform, beginning in calm water before moving to wide-area searches in different sea states off the Pacific coast. Just as importantly, the evaluation allowed fleet Marines to provide feedback directly to the program office while the system remains under development, helping refine operational relevance and the human-system interface before potential fielding.

For the Marine Corps, LEON also aligns with a broader modernization drive centered on operating effectively across contested littoral environments. The latest Marine Corps Force Design update emphasizes forces optimized to operate in the littorals, sense and shape the operating environment, support fleet maneuver and exploit increasingly autonomous systems. LEON directly supports that direction by seeking to expand how far EOD formations can sense and investigate threats while reducing the need to expose highly trained Marines unnecessarily. Its strategic contribution is therefore not simply replacing personnel with unmanned technology, but extending operational reach, preserving combat power and helping maintain freedom of maneuver in environments where explosive hazards could otherwise disrupt expeditionary operations. According to Portfolio Acquisition Executive Marine Corps, successful validation of the USV is expected to establish a pathway toward beginning fielding to Marine EOD companies in fiscal year 2027, while integration of the broader LEON family of systems is planned over the following two years.

LEON represents an important evolution in how U.S. Marines could detect and respond to explosive hazards across the critical transition between sea and land. By combining autonomous surface mobility, sonar and electro-optical sensing, underwater communications and a wider family of robotic systems, the Marine Corps is building an EOD architecture designed to extend operational reach while reducing unnecessary exposure of highly trained personnel. The USV's ability to search littoral areas, communicate with subsurface platforms and relay real-time information could make it a central link within the broader LEON System of Systems, helping Marine EOD teams identify hazards and support safer routes for follow-on forces. If validation and planned fielding progress as intended, the combination of sensing, endurance, connectivity and force protection could strengthen the Marine Corps' ability to maneuver, preserve combat power and operate effectively across increasingly contested littoral environments.

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Written by Teoman S. Nicanci – Defense Analyst, Army Recognition Group

Teoman S. Nicanci holds degrees in Political Science, Comparative and International Politics, and International Relations and Diplomacy from leading Belgian universities, with research focused on Russian strategic behavior, defense technology, and modern warfare. He is a defense analyst at Army Recognition, specializing in the global defense industry, military armament, and emerging defense technologies.