Trieste is a compact city and most of the central sights are walkable, though the terrain is hilly — the city climbs steeply from the waterfront up to the Carso plateau, and some streets involve serious gradients. The historic tram line up to the village of Opicina (the Tram de Opcina) has been closed for restoration for several years; check local sources for its current status.
City buses cover the centre and outlying areas well. The main bus hub is at Piazza Goldoni. Taxis are available but relatively expensive. For the Carso plateau and the Slovenian border area, a car is useful.