1. Go swimming!
Osijek may not have the sea, but that doesn't mean you can't enjoy swimming. In summer months, the open air Copacabana complex is teeming with people. Pay ten kuna and stay for as long as you like, taking advantage of multiple pools (although they can be very busy). Some locals prefer to stay immediately outside, swimming in the cool and refreshing Drava river. Be aware, this river has strong currents, so this option is only for strong swimmers and they are advised to stay near the banks. With ten pools and more available at renowned nearby spa Bizovac Toplice, their free transfers should also be taken advantage of.