There has been an increasing demand for sports facilities in urban areas recently. As a result of this, more attention is drawn towards not only the energy performance of these building typologies, but also creating a healthy indoor environment for its users. This study investigates the thermal and ventilation performance of a naturally and hybrid (assisted by exhaust fans) ventilated sports hall within an aquatic centre situated in the temperate climate of Victoria, Australia. Its evaluation predominantly considers continuous on-site measurements of air temperature stratification, thermal comfort, CO2 levels, thermal images and tracer gas ventilation studies. Further ventilation analysis is accompanied by CFD simulations towards the development of optimised conditioning strategies. A high level of thermal discomfort was observed for this space during a late summer period when over-heating is a concern. A number of energy efficient strategies are considered to improve the thermal comfort condition without adopting refrigerant conditioning and not sacrificing indoor air quality. A better understanding of how to improve and control such spaces primarily under a naturally ventilated condition is the outcome of this study. (C) 2012 Elsevier B.V. All rights reserved.