Swiss startup Tethys Robotics, a spin-out from ETH Zurich and now a leader in underwater robotics, has announced the successful closing of a €3.5 million pre-seed financing round.
The round was led by Redstone with Euregio+ & Alpine VC, and backed by Zürcher Kantonalbank, ETH Foundation, Kickfund, and Venture Kick.
The capital will be used to further develop and scale Tethys ONE: a compact hybrid underwater drone capable of both remote and autonomous operation.
The system is designed specifically for safety-critical missions, including inspections and maintenance in offshore wind, oil, and gas sectors, disposal of explosive remnants of war, and search-and-rescue missions under extreme conditions.
Tethys describes its new system as a “revolutionary technology for dangerous underwater deployments”.
The Tethys ONE drone was engineered with extreme use cases in mind. It weighs only 35 kg, is ready for deployment within 10 minutes, and operates at depths of up to 300 meters, even in low visibility and strong currents. This is made possible by a robust sensor fusion technology developed at ETH Zurich.
Jonas Wüst, CEO and co-founder of Tethys Robotics, says: “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.
“With the new funding, we’ll bring Tethys ONE into safety-critical applications worldwide and set new standards in underwater inspection.”
Tethys ONE is used, among other things, for the disposal of legacy ordnance from World War II. Over 1.3 million tons of explosive war material lie in European waters alone.
Rather than putting human divers at risk, the technology allows remote or autonomous missions with high-resolution 3D visualization for simplified navigation and automated data collection.
The drone is already being successfully tested with pilot customers in the offshore wind and energy sectors, assisting in the inspection of turbines, platforms, and subsea cables. Demand is high; more than 30 pilot projects have been launched.
Ben Scheidt, VC Investment Director at Redstone, says: “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.”
Beyond its focus on civilian applications, the company also plans to deepen collaboration with public safety authorities and international organizations in the field of ordnance disposal. Tethys already works with the Swiss Army and the Swiss Drone and Robotics Centre (SDRC).
