Underwater inspection and maintenance in challenging environments, such as offshore oil, gas, and wind farms, carries risks due to strong currents, low visibility, and deep dives. Human divers often face dangerous and costly conditions during these operations.
Tethys Robotics offers a solution with its autonomous hybrid underwater drone, Tethys ONE. Weighing just 35 kilograms, this drone can deploy quickly, navigate depths of up to 300 meters, and operate effectively in harsh underwater environments. It integrates advanced sensor fusion and AI-powered navigation technology to perform precise, automated inspections safely and efficiently.
The Swiss deep-tech startup, spun out of ETH Zurich in 2021, has recently secured €3.5 million in pre-seed funding. The round was led by Redstone, with investments from Alpine VC, Euregio+, Zürcher Kantonalbank, the ETH Foundation, Kickfund, and Venture Kick.
The funds will accelerate product development, expand the team, and enable global scaling.
Safe alternative for underwater missions
Tethys Robotics was founded by Jonas Wüst (CEO) and Pragash Sivananthaguru. Both have strong connections to ETH Zurich’s robotics research ecosystem. Wüst, holding a Master’s degree in Robotics, combines his academic background with practical diving experience, which informs the company’s commitment to safer underwater solutions.
Wüst tells TFN, “We started out of curiosity — building robots that could survive real conditions — and quickly saw a massive market gap: offshore work is still dangerous, expensive, and far from digital. We are changing that.”
Tethys ONE blends fully autonomous capabilities with multi-modal sensor fusion. It is equipped with sonar, 3D cameras, and metal detectors, driven by advanced AI navigation. Wüst elaborates, “Tethys ONE is a compact, hybrid AUV/ROV combining ETH-developed autonomy and sensor fusion with industrial reliability. It can operate remotely or fully autonomously, deploy in under ten minutes, and reach 300 m depth — without large vessels or dive teams.”
Unlike traditional remotely operated vehicles (ROVs) that depend on human pilots, Tethys ONE can function independently in turbulent and low-visibility conditions. Its modular design supports diverse applications, ranging from offshore wind turbine inspections to explosive ordnance disposal, a niche with few specialised competitors such as Eelume and Ocean Infinity.
“With our technology, we aim to enable fully autonomous underwater inspections – from data capture to analysis. That way, we deliver precise, reproducible results without human risk; faster, safer, and more efficient than ever before,” says Wüst.
The company’s readiness is validated through collaborations with the Swiss Army, Swiss Drone and Robotics Centre (SDRC), and multiple pilot programs.
What’s next?
Looking ahead, Tethys Robotics plans to enhance Tethys ONE’s autonomy, develop new payload modules, and expand its industrial applications, particularly in offshore energy and public safety.
Wüst concludes, “Scale serial production, expand across Europe, and enter the U.S. and Asia-Pacific markets. Technically, we’re advancing toward full autonomy and automated deployment (e.g. from remotely operated uncrewed surface vessels) — eliminating the need for people offshore entirely.”
“Tethys is a prime example of how globally impactful, tech-driven companies can emerge from the ETH Zurich ecosystem. With the Alpine Fund, we specifically support this fusion of scientific excellence and entrepreneurial boldness,” notes Ben Scheidt, VC Investment Director at Redstone.
