The concept of EMODnet Sea-basin Checkpoints was introduced within the Green Paper 'Marine Knowledge 2020: from seabed mapping to ocean forecasting' (COM-2012-437). In spite of EU initiatives such as EMODnet, Copernicus and Data Collection Framework (DCF) for Fisheries to deliver seamless layers of marine data across national boundaries, there are still shortcomings with the availability and accessibility of EU marine data. Data collections have been largely put in place for specific and/or national purposes. There is still an approximate overview on a sea basin scale of gaps and duplications and there is no overall view of what the priorities are for further data collection or assembly. Thus the EMODnet Checkpoint initiative will begin to link all existing monitoring data at the level of the sea basin and assess them in order to define their future improvements.