This article investigates the evolving security practices of one of the key actors in the handling of asylum-seekers and migrants at the external borders of the European Union (EU) Member States, the European Border and Coast Guard Agency, widely referred to as ‘Frontex’. It does so by applying a revised version of the Copenhagen School’s securitisation framework, which focuses on security practices and is underpinned by an understanding of security as belonging to a continuum. The article compares and contrasts the practices of Frontex in the context of two significant ‘migration crises’ in the Mediterranean, in 2005–2006 and 2015–2016, respectively. The analysis of the more recent practices of the Agency following the 2015–2016 ‘migration crisis’ shows that this ‘crisis’ has led to an intensification of the security practices of the Agency. Frontex has moved towards the end point of the continuum, which is characterised by survival, existential threats, and militarisation. This has contributed to a spiralling of the securitisation of migration in the EU.