This article investigates how railways, as infrastructure, fabricate and articulate an island’s identity (its ‘islandness’), from the perspective of a case study of Hainan Island in the People’s Republic of China (PRC). The development of the railway on Hainan is predominantly contextualised in terms of two distinct historical construction phases: the first stage is a brief colonial period under Japanese rule (1939–1945) in which railway development was undertaken for resource exploitation supporting colonial expansion and war supply; the second stage is the present-day development of a circular high-speed train network as part of the construction of the Hainan Free Trade Port (2023–2025). In the latter case, Hainan’s transportation infrastructure is more than a symbol of the modernisation of the island, it also affirms the image of the island as a type of tropical paradise for outsiders and mainland Chinese, aligning with the national vision of the island as an embodiment of extra-statecraft. This dominant narrative of Hainan, rooted in infrastructure, reinforces a tourist-centric identity and facilitates capital circulation. I argue that the complexity of Hainan’s islandness, grounded in railways as transportation infrastructure, reveals a counter-utopian perspective and resistance to colonial legacies, particularly from the perspective of intra-island circulation and its multifaceted cultural dimensions. This research not only spotlights underexplored realities of Hainan’s railway development but also sheds light on an emerging conceptual framework — the railway as means of circulation and narration — for understanding Hainan’s speculative infrastructure development and infrastructural promises for the future.