This article offers a fresh approach to the study of ‘Indo-Roman’ trade by defining the ‘players’ of the ‘game’ of Indian Ocean commerce in the early centuries of the Common Era. Numerous specialized personnel hailing from the Mediterranean, Near East, and Indian subcontinent were involved in the movement, processing, and sale of Indian Ocean commodities. Players throughout the ancient world formed principal-agent relationships, corporate structures, and diaspora communities based on shared heritage and profession to facilitate their efforts. These tactics lowered the transaction costs of commerce arising from a combination of factors: the seasonal monsoon winds restricting wind-powered travel; the asymmetry of information for traders operating abroad without a strong support network; and state interventions (e.g. targeted infrastructure projects and tariffs). Certain individuals attained competitive advantages by cooperating with states to regulate the very commerce in which they engaged (e.g. tax-farmers).