One-off export sales – unprecedented and unrepeated shipments of a specific product to a specific destination – are widespread. We argue that, despite their brevity, such experiences can enhance firms’ ability to export and expand their product and destination scope, albeit less so than experience from recurrent export episodes. Analysing anonymized official business account data of monthly export records spanning two decades for over 5000 Danish firms, we identify 86,150 unique new firm-destination-product export spells. At this level of granularity, 48% of spells are one-off. We find that past one-off exporting indeed increases the probability of initiating new recurrent exports in later periods. We show that cumulative effects of one-off experiences can lead to a sustained expansion of a firm’s export portfolio across products and countries. These insights challenge the perception that one-off episodes are merely costly trial-and-error attempts, suggesting instead that they foster export expansion through experience.