Vienna’s ultimate free festival is back, Donauinselfest 2026 takes over the island June 19, 21 with three days of non-stop live acts, DJ sets, and stages by the Danube. No tickets, no stress, just pure festival energy under the sun. Bring your squad, pack sunscreen, and get ready to vibe with the whole city. Crowds will be massive, so come early and stay late, you won’t want to miss a second.