This volume includes the proceedings of the NATO Advanced Research Workshop held in Tallinn, Estonia, June 27-July 1, 2005 entitled Data Fusion Technologies for Harbour Protection. The aim of the ARW was to understand the requirements and procedures for ensuring security at a Harbour/Port and analyse how the Data Fusion Technology can enhance the situational awareness and help improve performance for Harbour Protection. The ARW brought together harbour security domain experts (administrators, policy makers, etc.) with a group of technology experts of international standing in Data/Information Fusion and detection technology in order to provide a mutual understanding of needs and capabilities related to Harbour protection.