Growing global demand for natural rubber is driving deforestation due to the expansion of rubber plantations, with consequences for biodiversity, carbon storage, and local communities. There has been little attention given to these issues in Sri Lanka, where rubber production is central to economic growth. Although private initiatives and government regulations aim to reduce deforestation associated with these plantations, it is unclear if these measures effectively protect forests or limit associated risks in the supply chains of companies purchasing Sri Lankan rubber. This paper uses the TRACAST methodological framework and remote sensing to track natural rubber supply chains from Sri Lanka to the U.S and to identify hidden deforestation risks resulting from this trade. We estimate 196 km2 of forest were converted into rubber plantations between 2006 and 2016, including protected forests located in an emerging rubber frontier in southeast Sri Lanka. Our analysis identifies rubber traders and multinational tire manufacturers as key actors that hinder the traceability of rubber back to the plantations. This opacity increases the potential for unsustainably produced rubber to enter global supply chains of transnational corporations such as Loadstar (Michelin) and Nike. Most of these corporations have sustainable procurement policies, but the effectiveness of these policies is compromised by the lack of supply chain transparency. Integrating public and private sector management through inclusive multi-stakeholder initiatives and multi-level land use governance can help overcome these hurdles, prevent future deforestation, and assist Sri Lanka in moving towards more sustainable rubber production.