The new generation of ocean robots that navigate like sea creatures

Meet the robots that can see and hear in the dark depths of the ocean

When Jonas Wüst first met rescue divers in Switzerland, what struck him was not their courage, but how much risk still defined their work. “We realized how outdated it all was,” he recalls. “Divers were still sent into low-visibility waters to inspect wrecks, recover objects or deal with unexploded ordnance. It was slow, dangerous and often guesswork.”

That observation became the spark for Tethys Robotics, a Zurich-based spin-out from ETH Zurich that is now a catalyst in the disruption of undersea automation. The startup has just secured €3.5 million in pre-seed funding, led by Redstone with Euregio+ and Alpine VC, and supported by Zürcher Kantonalbank, the ETH Foundation, Kickfund and Venture Kick.

With new capital, the company plans to scale production, expand its autonomy and data pools, and move from pilot projects to full commercial operations across Europe. “The target is serial production and multi-unit contracts in offshore wind, oil & gas and defense by 2026,” he adds.

From University Laboratories to the Open Sea

Wüst and his co-founders built their first prototypes while studying and conducting research at ETH Zurich, one of Europe’s most prestigious technical universities. “ET gave us the playground,” he says. “We had access to labs, sensors and the freedom to test ideas. What started as a side project quickly grew into a serious mission.”

“In robotics, you’re always balancing speed and precision,” adds Wüst. “Move too slow and you lose momentum, move too fast and you break prototypes. We’ve learned to iterate hard, build, test, learn, iterate.”

“The backbone of Swiss innovation really made it possible,” says Wüst: in an environment where deep-tech startups often struggle to reach commercialization, Switzerland’s innovation ecosystem, including Wyss Zurich and the startup program Innosuisse, has been crucial to the startups’ growth.

The turning point came when the team realized how far autonomy could go underwater. an environment where GPS does not work and visibility is often almost zero. They built a sensor fusion stack that essentially mimics the way marine animals perceive and navigate underwater, but in a mechanical form. The auditory sense mirrors the way dolphins and whales use echolocation to “see” through sound. Magnetic and inertial sensing is similar to how some fish and sea turtles use Earth’s magnetic fields and motion cues to orient themselves.

Tethys underwater robots fuse acoustic, magnetic, inertial and visual data to locate and interpret the environment in real time. “It’s what makes reliable autonomy possible below the surface,” explains Wüst. Its technology has evolved – like marine animals – to have eyes and ears that work underwater.

Rethinking how underwater robots work

“Most underwater robots are either too bulky or too blind,” says Wüst. “It takes big boats, big facilities and skilled pilots. We wanted to make something that could be powered by two people, but smart enough to operate on its own.”

The company’s first robot, Tethys ONE, weighs 35 kg, deploys in ten minutes and dives to 300 meters. Despite its small size, it performs highly accurate surveying, mapping and detection tasks in conditions where visibility, temperature and currents would defeat most existing systems.

Operators can seamlessly switch between remote and self-guided modes, allowing the drone to plan routes, navigate and collect data independently, while giving humans full override when needed.

Industry observers say this transition is already underway in offshore sectors. “The industry is undergoing a remarkable change as emerging technologies demonstrate solid performance and build a solid track record, particularly in less complex applications, which are steadily expanding,” says Richard van der Tuin, DWT’s Head of Offshore Business Development. “Downhole survey operations, for example, are making significant strides towards full autonomy, while near-structure inspections are gaining momentum but face ongoing regulatory and technical challenges.”

While companies like Exail in France and Vatn Systems in Norway are pushing the limits of underwater autonomy, many underwater robots remain anchored in narrow sectors. primarily defense and security. The Tethys, however, straddles both worlds: compact enough for rapid civilian deployment yet powerful enough for military-grade missions. The same system that can map World War II corrosive munitions for defense customers can also inspect offshore wind turbines, monitor undersea infrastructure or support environmental surveys.

Clearing the invisible world below

The need for safe, efficient underwater access has never been greater. Offshore wind farms require constant inspection, while one of the least recognized environmental hazards is invisible: underwater munitions disposal. Across Europe, it is estimated that 1.3 million tons explosive material from World War II remains submerged. As the metal casings corrode, toxic compounds such as TNT and RDX leach into marine sediments, threatening ecosystems and coastal communities.

“Large areas are not even mapped,” says Wüst. “Our system can detect and classify munitions from a safe distance, produce 3D maps and help prioritize what needs to be removed or tracked.” By replacing divers with autonomous units, the approach reduces human exposure and speeds cleanup, a growing priority for governments and offshore operators.

Van der Tuin agrees that cost and safety are the two drivers driving this transformation. “Current operations typically rely on a wide spread of a vessel, personnel and equipment resulting in significant capital expenditure,” he notes. “Advances in robotics are dramatically reducing this footprint. They not only reduce the costs associated with data acquisition, but also streamline the processing of sensor data, paving the way for more economically viable and scalable deployment strategies.”

The same capabilities apply to the offshore wind and oil and gas sectors, which need regular inspections of turbines, platforms and submarine cables. According to a SkyTruth reportSatellite and artificial intelligence analysis found that twenty offshore oil and gas sites collectively leaked nearly 300,000 gallons of oil between June 2023 and October 2024. a reminder why the sector urgently needs better inspection and prevention tools.

After completing more than thirty pilot projects, Wüst says adoption is accelerating. “Customers are seeing ship time savings, faster mobilization and data they can use directly for asset management.”

Van der Tuin adds that these technologies could soon be extended to renewable energy infrastructure and conservation work. “With the expected reduction in capital footprint, thanks to robotic and semi-autonomous developments, operations are becoming significantly more efficient,” he explains. “Autonomous drones can preselect areas of interest, allowing larger traditional ROVs to be deployed only where necessary. This hybrid approach optimizes both cost and operational efficiency.”

The next frontier of underwater surveillance

“Today we automate inspection and mapping,” says Wüst. “Tomorrow, we’ll automate decision-making, data analysis and even deployment from unmanned surface vessels. No divers, unmanned vessels, just digital workflows from shore.”

This vision is already taking shape. As the connection between climate and defense technology becomes stronger, Tethys is working with the Swiss Army and the Swiss Drone and Robotics Center (SDRC) in defense and disaster response use cases, including flooded areas and search and rescue missions in murky waters. “Wherever people face danger underwater, autonomy can help identify, assess and respond faster,” says Wüst.

Van der Tuin believes that the complete replacement of divers will still take time, but the direction is clear. “While we are making significant strides towards reducing the need for human divers on dangerous underwater missions, full replacement is still some way off,” he says. “But equipment is now being built with robotic intervention in mind, minimizing the frequency of diver deployment, allowing remote or autonomous systems to handle mundane and predictable tasks.”

He adds that the barriers are both cultural and technical. “Evolving standards and certification requirements continue to mandate human oversight in many jurisdictions, and the industry’s reliance on diver expertise will take time and proven reliability to shift to autonomous solutions.”

Environmental monitoring is another area with growing potential. Operating silently and continuously, the Tethys robot can observe habitats, monitor pollution and monitor biodiversity without disturbing ecosystems, a capability that could redefine how ecologists collect long-term ocean data.

This convergence between climate innovation and defense technology reflects a broader shift. “There is a new generation of investors who no longer see sustainability and security as separate lanes,” says Ally LaTourelle Whitney, Founder of the Government Affairs Accelerator. “They think holistically, how technology reduces the risk of conflict and resource dependency. This fuels support for what some call ‘technology of peace’.”

In ten years, Wüst envisions a world where every offshore energy or environmental monitoring operation operates fleets of compact, autonomous drones that communicate with unmanned surface vessels “a future where the ocean economy operates safely, sustainably and fully digital.”

Underwater robotics proves that the future of autonomy isn’t just about self-driving cars. will revolutionize the way humanity interacts with the sea. “Our job is to build systems that handle risk so that people can handle data,” says Wüst.