ECOC 2025 editorial

The European Conference on Optical Communication (ECOC) 2025 was the 51st ECOC and was held in Copenhagen, Denmark, between 28 September and 2 October 2025. Overall, the event welcomed 8100 attendees, of whom 2100 attended the technical part of the conference. Papers presented consisted of tutorials, invited, and regular submissions. The very best of these, where the focus was on optical networks, were invited to submit an expanded paper to the Journal of Optical Communications and Networking , and this Special Issue is the result, comprising 13 papers.