As defence has skyrocketed to the top of the European agenda this year, investors have turned their attention to startups working to ensure the continent’s security. While drones and AI have hogged the headlines so far, VCs are increasingly interested in maritime tech, which is largely focused on protecting Europe and its subsea infrastructure.
“Maritime conflict is heating up globally, from undersea cable sabotage in the Taiwan Strait, Baltic and Black Sea, to contested waters in the South China Sea, Persian Gulf and Eastern Mediterranean,” Nathan Benaich, founder and general partner of AI-focused VC Air Street Capital, tells Sifted. “Control of subsea infrastructure is becoming a critical strategic lever too.”
Jack Wang, partner at Berlin-based Project A, adds that a recent scare, where two fibre optic cables in the Baltic sea were damaged as a Chinese ship was passing over late last year, has stoked interest in the sector — and the fear of underwater cable sabotage.
Climate change has also impacted the scope of what needs protecting. “With the melting of some of the ice caps, it’s opened up new routes that need to be monitored to protect nations,” says Alex Leigh, an investment director for Future Planet Capital, which manages an ocean-focused fund for the government of Monaco as well as a defence fund for the national UK Innovation and Science Seed Fund. “There’s a big drive towards autonomous drones, and that’s coming subsea. You might soon have swarms of drones subsea that you want on your team, and the opposing team might have them as well — so you need a way to detect them and perhaps [use] deterrence.”
Total funding for water and maritime startups is up 107% year-over-year for the first half of this year, with €342m in funding for the first six months of 2025, compared to €165m for the same period last year, according to Sifted data.
It’s not just defence: VCs also say maritime tech is a big untapped market. “The ocean is 70% of the planet and maritime autonomy is becoming technically viable: breakthroughs in navigation with GNSS-free positioning [without satellite], sensing, and multi-agent systems are unlocking real deployments,” adds Benaich.
“It’s a very underserved market, because it’s historically been known to be quite archaic, slow moving, etc.,” notes Leigh. “If you look at the computer systems and the cybersecurity or lack thereof on ships, it’s decades behind terrestrial applications.”
From quantum to autonomous boats
Maritime tech has grown into a lot more than just ships.
Benaich says Air Street is investing in “full-stack” companies building both hardware and software for sea autonomy. He points to Swedish portfolio company Polar Mist, which makes maritime drones and is building an optical, GPS-free positioning system that it says doesn’t drift over time to prevent navigational errors. The startup is also backed by former CIA officer Eric Slesinger via his new VC firm 201 Ventures.
Another of Benaich’s favourites, Athens-based Delian, recently launched an autonomous naval and aerial interceptors product — drones and boats that can attack — for things like ocean defence and border surveillance. “There’s a huge open space across [intelligence, surveillance and reconnaissance], subsea surveying, [electronic warfare], logistics and infrastructure protection,” he says.
Others like Aquark Technologies, a UK-based company backed by Future Planet Capital, are working on using quantum tech for navigation. Leigh says the startup is building atomic clocks. “In time [they] will be used for inertial navigation, where you have GPS denied environments, and then also surface gravity applications such as seeing below the surface without having to dig or sink below the ocean floor, based on the gravitational pull.”
The company has done some trials on a British Royal Navy ship, which he believes is a fitting customer for the tech. Navigation “has been a challenge in the navy for the last 200-300 years. With the GPS jamming that we’ve seen over Ukraine, you can’t take satellites for granted anymore — hence why people are looking for these non-reliant solutions.”
Amsterdam-based Optics11 works on underwater surveillance; the company focuses on fibre optic cables and advanced detection software to monitor security breaches and other threats to energy and maritime infrastructure, and recently raised €17m in funding.
Autonomous maritime vehicles are also a big trend. “Unlike aerial or land drones where they can rely on computer vision, offshore/open water navigation largely still rely on radar and GPS since open oceans do not provide useful reference points for computer vision,” notes Wang. “Similarly a GPS jammer system in open water would be largely visible and quickly become a target.”
UK-based Kraken Technology just raised undisclosed funding from investors including the NATO Innovation Fund for its unmanned surface and subsea vehicles; Nordic startup Maritime Robotics is also working on unmanned water vehicles for things like environmental monitoring and surveillance.
While VCs are certainly excited about defence applications, they also point to commercial use-cases — and some companies’ tech could be used by big oil companies, too.
Honuworx, based in Scotland, is working on subsea remote-operated vehicle services. Leigh says it’s “hugely inefficient” for oil companies like Shell or BP to turn a valve in the ocean, requiring them to charter expensive vessels, burn a lot of diesel and cause emissions, hire a crew and wait for perfect weather conditions.
Honuworx delivers “basically a mini submarine” with a remote operated vehicle inside to go underwater and do the operation itself — like servicing wind farms or fixing gas pipelines. “It’s bringing autonomy to one of the most hostile environments,” adds Leigh, referring to the ocean. The small, remote operated submarines could also be useful for defence applications, he says: “If it’s a defence customer, you’ve got a big footprint. You can be seen from space. You’re a target.”
Maritime tech’s challenges
Betting on sea-focused startups could also be a choppy ride for VCs; investors say there are a number of challenges for maritime companies.
“Unmanned underwater systems are notoriously difficult to build since they largely rely on sonar sensors [because] computer vision and GPS does not work well underwater,” and “the vessel, depending on depth and what it is detecting — e.g. submarines — needs to be water proof and pressurised, which is a different set of engineering challenges to other [unmanned] products,” says Wang.
Benaich believes “foundational work” still hasn’t been done. “GNSS-free positioning was an obvious gap for years. The environments are harsh, expensive to test, and operational excellence matters, but that’s exactly where durable companies get built.”
Wang adds that unmanned underwater vehicles in Europe remains “largely unsolved and early stage” owing to some of those challenges, but that companies like defence tech unicorn Helsing are becoming more actively involved in maritime tech; Helsing recently announced an underwater surveillance system.
“I think there is an imperative now for maritime because of the threat environments,” Leigh adds. “We need to protect ourselves.”
Read the orginal article: https://sifted.eu/articles/maritime-tech-vc-investment-defence/
