We analysed the impact of exporters’ social media use on export costs and relationships with foreign customers using data collected in 2013 and in 2021. Our empirical results show that better information and communication technology (ICT) capabilities positively influence social media use, enhance communications, and lead to stronger relationships with foreign customers, but do not directly reduce export costs. We highlight the significant mediating role played by exporters’ cross-country social media communication in relationship building with foreign customers. Some divergences were evident in relation to the effects on export costs in 2021 compared to 2013. In 2013, social media communication, but not relationship building, notably reduced export costs; in 2021, in contrast, marked by the increased use of social media by consumers and companies due to the COVID-19 pandemic, the scenario was reversed: relationship building, but not social media communication, exerted a notable influence on costs. Commented, in conclusion, are the theoretical and practical implications of exporters using social media to improve their internationalization.