The subject of coopetitive strategies has been increasingly studied since the end of the 1990s in academic literature on strategic management, offering an in-depth renewal of the way of looking at the evolution of exchange relations between firms, and emphasizing that neither pure cooperation nor pure competition are satisfying explanatory models of the reality of business. In fact, cooperation and competition blend to give rise to a novel model of value creation: coopetition. The paper makes use of this conceptual framework to study the role of third party logistics (3PL) in the operation of modern supply chains. 3PLs appear to be the catalysts of coopetitive strategies, particularly when they manage modular platforms. An exploratory field study conducted in France has identified three 3PL archetypes in the dynamics of coopetitive supply chains: 3PL as caretaker, 3PL as lead operator and 3PL as architect.