Vesicular transport was key to the evolution of eukaryotes, and is essential for eukaryotic life today. All modern eukaryotes have a set of vesicle coat proteins, which couple cargo selection to vesicle budding in the secretory and endocytic pathways. Although these coats share common features (e.g. recruitment via small GTPases, β-propeller-α-solenoid proteins acting as scaffolds), the relationships between them are not always clear. Structural studies on the coats themselves, comparative genomics and cell biology in diverse eukaryotes, and the recent discovery of the Asgard archaea and their 'eukaryotic signature proteins' are helping us to piece together how coats may have evolved during the prokaryote-to-eukaryote transition.