Sweden’s unmanned mini‑submarines are entering development in Karlskrona to strengthen Baltic Sea surveillance. The Swedish Defence Forces (Försvarsmakten) are working with the Defence Materiel Administration (Försvarets materielverk, FMV) and Saab Kockums on a new Large Uncrewed Undersea Vehicle (LUUV), with the first prototype due in the water by summer 2026 under an accelerated procurement.
Why unmanned mini‑submarines now
The project responds to a heightened security environment in and around the Baltic, where seabed infrastructure—from gas pipelines to data cables—requires tighter monitoring. By deploying uncrewed underwater vehicles (UUVs) ahead of manned submarines, the navy can map mines and seabed sensors, reduce risk for crews and extend coverage across contested littorals.
The current LUUV demonstrator is planned at 5–6 metres in length and roughly 1.5 metres in diameter. It can be launched by harbour or shipboard cranes, or via locks on larger submarines. The goal is AI‑enabled autonomy allowing operations of up to one week without recovery, focused on reconnaissance and intelligence collection in the Baltic Sea.
From Kockums build to 2026 sea trials
Construction began at Kockumsvarvet (Saab Kockums) in Karlskrona through a fast‑track acquisition initiated this summer. Initial sea trials are scheduled for summer 2026. In the first phase, the platform is unarmed and serves primarily as a sensor platform.
In the longer term, the navy indicates the mini‑submarines could be fitted to deploy mines or lightweight torpedoes, subject to future decisions. The system is designed to precede manned submarines—Sweden currently operates four—to clear and survey high‑risk areas before crewed assets move in.
Budget and industrial team
FMV has placed an initial development order with Saab valued at SEK 60 million (approximately €5–6 million). According to the navy, the overall project budget remains classified but is under SEK 100 million (under €9 million).
The programme brings together Försvarsmakten, FMV, Saab Kockums, and is expected to involve the Swedish Defence Research Agency (Totalförsvarets forskningsinstitut, FOI) and academia.
Baltic security and European relevance
LUUV fits a broader regional push to monitor the seabed domain after a series of Baltic Sea infrastructure incidents. For Nordic and EU partners, Sweden’s move signals a shift toward modular, autonomous systems that can be networked across allied fleets. As integration deepens, shared data standards and joint exercises will be crucial to maximise deterrence and situational awareness in shallow, cluttered waters.
The key milestones are prototype launch and trials in 2026, rapid iteration toward pre‑series units, and decisions on payloads and rules of engagement for semi‑autonomous operations. For the Nordic region and the EU, the programme’s progress will test how quickly autonomy can be scaled to protect the Baltic Sea while aligning with legal and ethical constraints.
