TROIA, Portugal — Representatives from the Ukrainian navy participated in NATO’s largest unmanned maritime systems exercise this month, simulating the opposing force to test the capabilities of two dozen allied countries in scenarios inspired by frontline action.
Ukraine was one of 24 countries that took part in the Portugal-led military exercise, REPMUS 2025, from Sept. 1-26, dedicated to testing hundreds of autonomous systems for naval applications.
Captain Valter de Bulha Almeida of the Portuguese Navy told reporters that Ukrainian forces took on the role of the adversarial “red team,” with scenarios shaped by what they were seeing on the battlefield in their defense against Russia.
“The question is not who is winning, I am much more interested in developing tactics – we’re learning a lot from Ukraine, I can guarantee you that, because we have to act as if the threat is real, so they are doing what they do and see on the front lines, and for us it’s very important,” he said during a Sept. 24 media briefing at the Portuguese Navy Operational Experimentation Centre (CEOM) in Tróia.
The official added that Ukrainian unmanned surface vessels participated in the exercise, but did not provide more details, citing security reasons.
A presentation of REPMUS capabilities broke down the number of unmanned assets between the two different teams: the red team was listed as having 61 drones, 57 USVs and one unmanned ground vehicle.
Images purportedly showing an upgraded variant of the Magura V7 drone boat at the CEOM port, produced by the Ukrainian state-owned company SpetsTechnoExport, or STE, were first published by the Portuguese defense blog Defence360.
When asked to confirm the craft’s presence for the exercise, an STE representative told Defense News that the company had no comment, but provided a link to a report from the Ukrainian media outlet Militarnyi detailing the naval drone’s presence in Portugal.
The deployment of Magura naval drones throughout the war has been widely documented. In 2023, at the DSEI trade show in London, the Ukrainian company shared a white paper stating that the Magura V5 was “the world’s first maritime drone with public video confirmation of hitting legitimate targets, including [Russian] warships.”
According to Militarnyi, in this configuration, the Magura V7 weighs approximately 3,400 kilograms and can cover distances of up to 1,500 kilometers.
Naval drones are becoming increasingly common in European militaries.
In 2023, the Portuguese Navy established its first squadron-sized drone unit, which officers here said was directly inspired by the situation on the Ukraine battlefield.
Dubbed X31, the group falls under the authority of the naval command and is primarily responsible for testing and operating aerial, surface, and subsea unmanned systems. It also contributes to the development and coordination of drone warfare doctrine.
Some of the systems the unit is currently trialling were present at REPMUS, including the Trator Do Mar, developed by the Portuguese Navy’s Unmanned Vehicles Operational Experimentation Cell (CEOV). The USV is designed for maritime domain awareness and sea-bed mapping, but is not yet in service.
A particularity of the NATO exercise this year was that jamming trials were carried out daily between 5-6 p.m. to test the exercise drones in combat-like environments.
Elisabeth Gosselin-Malo is a Europe correspondent for Defense News. She covers a wide range of topics related to military procurement and international security, and specializes in reporting on the aviation sector. She is based in Milan, Italy.