U.S. Marines Launch Island Assault with Sweden’s CB90 Amphibious Assault Crafts in Baltic Sea Drill.

On September 18, 2025, the U.S. Army officially reported that U.S. Marines from Alpha Company, 2d Light Armored Reconnaissance Battalion, 2d Marine Division, executed a joint island raid in Korso, Sweden, aboard Swedish CB90 fast assault craft as part of Exercise Archipelago Endeavor 2025, held on September 7. The maneuver, which saw integrated operations between American and Swedish forces, highlights a sharpened amphibious readiness in the increasingly contested Baltic Sea. Amid heightened regional tensions, this bilateral drill reflects a significant escalation in combined training complexity and scale between the U.S. and its new NATO ally Sweden. The exercise underscores deepening interoperability while simulating real-world island warfare scenarios just miles from Russian air and naval corridors. 
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Exercise Archipelago Endeavor 2025 not only reinforced U.S.-Swedish military ties but also demonstrated the combat utility of indigenous Swedish platforms like the CB90 in modern expeditionary warfare (Picture source: U.S. Army)

At the core of this operation were Sweden’s Combat Boat 90 (CB90), high-speed amphibious assault craft known for their agility, stealth, and precision in littoral environments. Designed by Dockstavarvet and fielded by the Swedish Navy, the CB90 boasts a shallow draft, dual waterjets, and a reinforced hull that allows it to deliver troops at high speeds in archipelagic terrain. During the raid in Korso, these craft transported U.S. Marines swiftly to insertion points while evading simulated opposition forces and maintaining low radar visibility. Supported by LAV-25 light armored vehicles and integrated with Marine Corps reconnaissance elements, the CB90s formed the spearhead of a complex raid across rugged coastal terrain.

The CB90 has long been a cornerstone of Swedish coastal defense, particularly suited for operations in the country's fractured Baltic coastline. Since its introduction in the 1990s, it has evolved through several variants and been exported to Norway, Mexico, Greece, and Malaysia. Notably, the U.S. Navy and Marine Corps have also evaluated the platform in littoral combat trials, recognizing its value in expeditionary advanced base operations (EABO). This latest exercise marks one of the most integrated uses of the CB90 by U.S. forces, blending NATO standardization with Swedish amphibious doctrine honed in complex coastal defense scenarios.

The CB90 offers superior speed, maneuverability, and load capacity compared to other small assault craft such as the U.S. Navy's Riverine Command Boat or the older Mark V Special Operations Craft. With speeds exceeding 40 knots and capacity for 21 fully equipped troops, the CB90 can rapidly redeploy infantry and conduct precision coastal insertions under hostile conditions. Its modular design supports various mission packages including medevac, command and control, and fire support. Unlike its American counterparts, which often require support from larger vessels for sustained operations, the CB90 is optimized for independent operations in confined waters, making it ideal for Baltic, Arctic, and archipelagic theaters. For the U.S. Marine Corps, exposure to this platform within a NATO training framework provides a significant capability boost as it shifts toward smaller, more agile units in the Force Design 2030 restructuring.

The joint amphibious operation conducted during Archipelago Endeavor 2025 signals a strategic recalibration of NATO’s northern flank, with Sweden’s full NATO accession now translating into practical military alignment. The presence of U.S. Marines operating from Swedish craft in the Baltic Sea directly strengthens the alliance’s ability to project power and conduct distributed operations across contested maritime terrain. As Russia expands its A2/AD (Anti-Access/Area Denial) posture in Kaliningrad and the Arctic, exercises like this send a calibrated message: NATO is preparing for flexible, forward-based responses in the most challenging environments. The use of CB90s in a simulated island seizure further illustrates how Sweden’s localized maritime expertise is being woven into broader U.S. Indo-Pacific-style amphibious concepts, adapting them to European scenarios. Strategically, it reaffirms the U.S. commitment to defend NATO's northern perimeter and ensures that future conflict scenarios involving hybrid warfare in the Baltics are met with joint operational fluency.

Exercise Archipelago Endeavor 2025 not only reinforced U.S.-Swedish military ties but also demonstrated the combat utility of indigenous Swedish platforms like the CB90 in modern expeditionary warfare. For the U.S. Marine Corps, this was more than a training event, it was a live rehearsal of future conflict scenarios where agility, interoperability, and maritime dominance will determine the outcome. As tensions in the Baltic Sea intensify, joint exercises of this caliber serve as critical deterrent signals and provide invaluable readiness for near-peer confrontation in Europe’s most volatile maritime corridor.

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.