Linz has a tram network (the Linz AG Linien) covering the main routes through the city, including the north-south axis across the Danube via the main bridge. The Hauptplatz is the hub for most tram routes. Tickets can be bought at tram stops or via the city transport app. Day passes are good value if you plan to use the tram several times.
The Pöstlingbergbahn, the steep tramway that climbs the Pöstlingberg hill, is part of the integrated tram network and uses the same tickets as the city trams — unlike in the past, when it required a separate fare. This integration happened in 2009 when Linz became European Capital of Culture.
The Old Town is compact and flat and is best explored on foot. The Danube riverfront promenade on both banks is a pleasant walking circuit. Cycling infrastructure is reasonable, and there are bike-share stations around the centre.