This chapter explores the various ways in which borders act as barriers and obstacles in the European Union, and why borders maintain this function even in a context of openness. While most formal barriers to the mobility of goods, capital, services, and labour (i.e. the “four freedoms”) have by now been removed within the European Union, the effects of borders persist. For people living close to borders, these function as obstacles that are related to communication and infrastructure, legal and administrative differences, as well as language and culture. Opinion polls and consultations with European stakeholders witness the importance of addressing regulatory (legal and administrative) obstacles, especially in the fields of labour and education, while language is an important obstacle where more could be done. The chapter finishes with policy recommendations to practitioners seeking to conduct and/or improve systematic policy work to remove border obstacles for enhanced territorial cohesion and regional development. © Springer International Publishing AG, part of Springer Nature 2018.