The use of satellite radar data to detect oil at sea started in the early 90-ties. A first generation service has been developed through activities like research and development, demonstrations, trials and end user feedback. The improvement of the service has been on-going under the support of national and European (ESA, EC) R&D programs. Up till 2005, the oil spill detection activities were strongly project- driven and the service was delivered to a core user group particularly in Northern Europe on a year-to-year basis. In 2007 European Maritime Safety Agency (EMSA) launched the CleanSeaNet (CSN). CSN is a pan-European satellite based oil monitoring service. The service operations have documented a need for development and improvement.The overall objective of the project is to improve the current state-of-the-art methodology for satellite based oil spill detection and impact assessment and to demonstrate through deliveries to existing and new users how these improvements can contribute the development of a sustainable service. This shall be done by integrating new geoinformation products and improved or new innovative methods. The project shall demonstrate a next generation service compliant with existing and new users expectations.The EMSA/CSN service represents the state of the art for the satellite based oil detection service. The CSN service has proven its operational value. However, the experienced end users require improved quality and enhanced functionality.SeaU will be a collaborative approach towards a harmonised pan-European service which will take full advantage of the products provided by Marine Core Service.