2015 saw the arrival of over one million asylum seekers in the EU, sparking what is now known as the European refugee crisis. The majority of those coming into the EU were doing so by boat from Turkey to Greece and then heading North, mainly to EU States such as Germany and Sweden. In order to deal with this so-called crisis, from September 2015 to March 2016 a number of EU and non-EU States along the Western Balkans route began to implement deterrence and prevention measures in order to reduce the number of asylum seekers entering their territories. This paper focuses on these measures and the implications of them for the right to seek asylum in the EU. Analysing how the right to seek asylum functioned in the EU before the crisis, this paper then maps the measures that have been implemented and examines the consequences of these. This paper finds that over the research period the ability for an asylum seeker to exercise their right to seek asylum in the EU became increasingly difficult with routes and mechanisms effectively becoming cut off. The measures can be interpreted through the idea of States regaining their sovereign decision-making powers over who may enter and remain on their territory, alongside how States may stretch the rule of law in times of exceptional pressure.