The NATO Cooperative Cyber Defence Centre of Excellence (CCDCOE) today commenced Locked Shields 2026 in Tallinn, Estonia. The exercise brings together more than 4,000 cyber defenders from 41 nations to strengthen the protection of national systems and critical infrastructure against sophisticated cyber threats.
„Cyber threats are becoming more frequent and increasingly sophisticated across the globe. We must be able to develop our cyber defence capabilities to stay at least one step ahead of them. Locked Shields unites the power of 41 allies and partners to exercise multinational cyber defence in a crisis and wartime scenario, exchanging know-how and enhancing collaboration, which is essential for long-term resilience to cyber threats,“ stated Tõnis Saar, Director of NATO Cooperative Cyber Defence Centre of Excellence.
The exercise simulates a realistic, large-scale cyber conflict in which the 16 participating teams take on the role of a multinational Rapid Reaction Team deployed to assist a fictitious ally Berylia under sustained attack. Over the course of two days, teams must defend a simulated national infrastructure against approximately 8,000 real-time cyberattacks – targeting systems including power grids, 5G networks, satellite and battle management systems.
Beyond technical defence, teams must navigate complex challenges in strategic communications, international law, digital forensics, and national-level decision-making. This holistic approach ensures that participants are well-prepared to handle all these complexities also in real life.
“Our core mission is protecting the systems that keep a nation running, from the power grid to air defense. But this year, we’re going further,” says Dan Ungureanu, Locked Shields 2026 Exercise Director. “By introducing a new election system in the Exercise, we are training our experts to safeguard the very foundation of our member nations: their democratic integrity.”
Locked Shields has been organised annually by the NATO Cooperative Cyber Defence Centre of Excellence (CCDCOE) since 2010. Although Tallinn serves as the primary site, the teams participate remotely from their respective countries across the globe.
The realism and effectiveness of the exercise rely on close collaboration with academia and industry partners, whose contributions are essential to its design and execution. They ensure operational relevance and authenticity, and enable the integration of advanced technologies, including AI, across key components of the exercise. In total, more than 100 industry partners contribute to this year’s iteration. Locked Shields is supported by official sponsors such as Siemens, Mattermost, and Bitdefender, who, in addition to their sponsorship, provide critical expertise and advanced technological capabilities required to design and sustain such a complex environment.