The International Conference on ns-3 (ICNS3) formerly known as Workshop on ns-3 (WNS3) will be held on October 19-21, 2026 at the University of Naples Federico II, Italy. The objective of this conference is to bring together ns-3 users and developers, networking simulation practitioners, and developers of other network simulation tools, together with an increasing number of industrial users, to discuss the ns-3 tool and related activities.