Literature exploring the role of African regional economic communities (RECs) have greatly expanded since the 1990s, focusing on a range of issues from borderlands to globalisation. Yet current research has rarely focused on the relationship between RECS and the extraction and export of raw materials, despite the importance of this to Africa’s position in the world economy. Instead, literature surrounding mining and hydrocarbon extraction has tended to focus on the national and the local level in terms of analysis. Yet, the discovery of hydrocarbon deposits in East Africa provides the opportunity to research how oil and gas affects the political economy of regionalism. East Africa has been a region with a long history of (attempted) political integration and economic harmonisation, culminating with the East African Community (EAC), but with a no history of hydrocarbon production. This has changed with commercial discoveries in all three of its founding members: Kenya, Tanzania and Uganda. While the transformative effects of hydrocarbons have been well explored, there has yet to be analysis on how this can affect the political economy of RECs, and how oil revenues can prompt or obstruct a shift towards different forms of regional cooperation. Drawing on interviews and documentary evidence from recent fieldwork in Tanzania and Uganda, this paper explores the effects commercial hydrocarbon production and exploration on the EAC’s integration trajectory. It argues that hydrocarbons can generate friction between national development and regional integration but also offer now forms of integration in the process. By doing so, it aims to expand the spatial scale of analysis of the transformative effects of hydrocarbon exploration and production to a regional level, and generate a better understanding of how hydrocarbons are affecting the process of regional integration.