O_WESTERSCHELDE - Eurasian oystercatchers (Haematopus ostralegus, Haematopodidae) breeding in East Flanders (Belgium) is a bird tracking dataset published by the Research Institute for Nature and Forest (INBO). It contains animal tracking data collected by the LifeWatch GPS tracking network for large birds (http://lifewatch.be/en/gps-tracking-network-large-birds) for the project/study O_WESTERSCHELDE, using trackers developed by the University of Amsterdam Bird Tracking System (UvA-BiTS, http://www.uva-bits.nl). The study has been operational since 2018. In total 13 individuals of Eurasian oystercatchers (Haematopus ostralegus) have been tagged in their breeding area in East Flanders (Belgium), west of the river Scheldt, mainly to study their habitat use on mudflats of the Western Scheldt (the Netherlands).