Investigation of thermal comfort in various types of buildings is a rather intense research activity by recent years. However, thermal comfort studies in sport facilities are very limited. Aquatic centers present an interesting field, in terms of Indoor climate and Air Quality, due to the fact that environmental quality is affected from high percentage of relative humidity, as well as from the emission of chemicals used for water disinfection. The proposed work presents a measurement campaign in a naturally ventilated aquatic centre in Western Macedonia, Greece. The campaign was performed through summer time, including measurements of thermal comfort and IAQ parameters. As far as thermal comfort is concerned, the approach of Fanger, as well as the adaptive one are considered. The results support the redesigning of the air-conditioning concept implemented, to ensure satisfactory thermal comfort conditions; energy consumption increase aspects should be taken into account.