This paper examines the bus rapid transit (BRT) legacies of mega sporting events (MSEs) held in the Global South cities of Cape Town and Rio de Janeiro. It discusses the extent to which these transport systems have been operationally sustainable, post-MSE; in other words, their ability to be maintained at a certain rate or level and hence their ability to act as public good as planned and according to specific needs. It argues that in both cities, long-term operational challenges have emerged due to conflictual temporalities between the priorities of the MSE and the mid/long term requirements of a transport system, supplemented by a poor spatial contextualisation of BRT design. These include financial viability, providing a service with appropriate frequency and capacity, integration with other transport systems, and resilience to external shocks such as extreme weather. These findings have key academic and policy implications both by opening further areas of research towards MSEs as a tool to deliver sustainable urban transport, and provides important lessons for future MSE hosts and cities considering BRT.Sustainability 2020, 12, 1609 2 of 17 there is very little insight into how these MSE-led infrastructures have been delivering the purposes for which they have been built, and specifically how the MSE imperatives may have affected its long-term development. In other words, we look here at the possible tensions of priorities between short-term ambitions (MSE) and long-term everyday needs. This indeed has a key impact on the authorities and operators who manage and fund public transport systems, and on the passengers who rely on it. To achieve this, the paper uses the term of operational sustainability, which is here shaped around the aim of assessing conflicting temporalities during setup of the project and hence reflecting on the wider implications for the long-term running and management of the network. We do so by bringing together the literature on MSE, sustainability, transport management, and infrastructure [8][9][10][11][12].This paper focuses on two cities whose transport network has been significantly impacted by hosting MSEs: Cape Town (South Africa) with the 2010 FIFA Football World Cup, and Rio de Janeiro (Brazil) with the 2016 Olympic Games. Each city constructed new bus rapid transit (BRT systems) under the auspices of hosting a MSE, and self-identified this in their proprietary communications and strategies as a transport legacy of the MSE. Through interviews with key stakeholders located in each city, this study assesses the benefits of the MSE for transport within the cities, such as reduced travel time in Rio de Janeiro, and a step-change in the quality of transport provision in Cape Town. It also considers the longer-term operational challenges such as financial viability that these BRT systems are facing post-MSE because they have not been sufficiently contextualised to the local transport situation and/or aligned with existing plans or policies. It is worth noting that this comparative rese...