LOCKED Shields 2026 was described as the world’s largest live-fire cyber defence exercise, bringing together more than 4,000 participants from 41 nations and concluding on Friday. Organised by the NATO Cooperative Cyber Defence Centre of Excellence (CCDCOE) in Tallinn, Estonia, the event simulated real-time cyberattacks against critical infrastructure and military systems to test defenders’ ability to maintain essential services under pressure.
The exercise again featured about the same number of participants as 2025, with sixteen multinational teams competing, and the top three joint teams were France and Sweden; Latvia and Singapore; and Germany, Austria, Luxembourg, and Switzerland. Teams were tasked with protecting air defence and e-voting platforms, among other assets, while also examining responses to disinformation and political pressure.
According to NATO CCDCOE’s director, the exercise demonstrated strong capabilities in detecting and responding to malicious activity, and underscored the need to translate lessons into real-world readiness as AI reshapes cyber defence and attack capabilities.