Open Air swimming pool in Andritz, a northern suburb of Graz. Also you can go to St Margarethenbad, in the town, you can get Student discount (40ATS for as long as you like at the time), but it's got damn cold water!!
Equipment: Swimming togs
Don't forget to visit the ArnoldSchwarzenegger stadion while in Graz. There is a gym at the back of the stadium which has a museum dedicated to the athlete/ actor/ politician.
The stadium is shared by Graz's two top football teams - Sturm Graz, who dominated Austrian football in the late nineties and Grazer AK (or GAK) who won the title last season for the first time ever in their history.