If a diplomatic cocktail party lasts two hours, does it equal the duration of peace? Or are there less simplistic conceptualizations of ‘peace’ and ‘time’ for the theorization of diplomatic practices? This article draws on a concept of temporality based on an irreversible before/after distinction, and combines it with the modern systems theoretical premise that every event within the diplomatic system occurs under the medium of peace, finding that: (a) peace is not a state of affairs, but a medium of communication; (b) peace has no chronometric duration, but it is temporally minimal, vanishing as soon as it appears; (c) peace needs constant reproduction, i.e. the system of diplomacy regenerates itself by continuously triggering further peace-mediated events; and (d) peace is both negative and positive, as it denotes a restraint of violent capacities but needs active communication. These insights offer a universal concept of ‘peace’ that is abstract enough to cover every interpolity tie. They also suggest further research opportunities, including into what the rapid acceleration of society means for the proliferation of ever-quicker, ever-more-trivial diplomatic practices.